Ultra-low latency lte reference signal transmission

ABSTRACT

Various aspects described herein relate to communicating in a wireless network. A resource grant comprising an indicator of whether to transmit a demodulation reference signal (RS) for an uplink control channel or an uplink data channel can be received from a network entity. It can be determined whether to transmit the RS in at least one transmission time interval (TTI) based at least in part on the indicator.

CLAIM OF PRIORITY UNDER 35 U.S.C. §119

The present application for patent claims priority to ProvisionalApplication No. 62/056,281 entitled “ULTRA-LOW LATENCY LTE UPLINK FRAMESTRUCTURE” filed Sep. 26, 2014, Provisional Application No. 62/056,397entitled “ULTRA-LOW LATENCY LTE CONTROL DATA COMMUNICATION” filed Sep.26, 2014, and Provisional Application No. 62/056,403 entitled “ULTRA-LOWLATENCY LTE REFERENCE SIGNAL TRANSMISSION” filed Sep. 26, 2014, whichare assigned to the assignee hereof and hereby expressly incorporated byreference herein.

BACKGROUND

Described herein are aspects generally related to communication systems,and more particularly, to an uplink frame structure and method of uplinktransmission for managing communications with user equipment in awireless communication system.

Wireless communication systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,and broadcasts. Typical wireless communication systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources (e.g., bandwidth,transmit power). Examples of such multiple-access technologies includecode division multiple access (CDMA) systems, time division multipleaccess (TDMA) systems, frequency division multiple access (FDMA)systems, orthogonal frequency division multiple access (OFDMA) systems,single-carrier frequency division multiple access (SC-FDMA) systems, andtime division synchronous code division multiple access (TD-SCDMA)systems.

These multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. An example of a telecommunicationstandard is Long Term Evolution (LTE). LTE is a set of enhancements tothe Universal Mobile Telecommunications System (UMTS) mobile standardpromulgated by Third Generation Partnership Project (3GPP). It isdesigned to better support mobile broadband Internet access by improvingspectral efficiency, lower costs, improve services, make use of newspectrum, and better integrate with other open standards using OFDMA onthe downlink (DL), SC-FDMA on the uplink (UL), and multiple-inputmultiple-output (MIMO) antenna technology. However, as the demand formobile broadband access continues to increase, there exists a need forfurther improvements in LTE technology. Preferably, these improvementsshould be applicable to other multi-access technologies and thetelecommunication standards that employ these technologies.

In wireless communication systems employing legacy LTE, a plurality ofUEs served by a particular eNodeB may be scheduled resources forcommunicating with the eNodeB over one or more uplink channels, such asa physical uplink control channel (PUCCH), physical uplink sharedchannel (PUSCH), etc. In legacy LTE, each LTE subframe includes acontrol region during which the control information is to be transmittedvia the PUCCH and a data region during which data is to be transmittedvia the PUSCH. In addition, the UEs transmit over the PUCCH and/or PUSCHin transmission time intervals (TTI) on the order of a 1 millisecondsubframe.

As UE capabilities and demand for bandwidth increases, lower latency incommunications may be desired.

SUMMARY

The following presents a simplified summary of one or more aspects inorder to provide a basic understanding of such aspects. This summary isnot an extensive overview of all contemplated aspects, and is intendedto neither identify key or critical elements of all aspects nordelineate the scope of any or all aspects. Its sole purpose is topresent some concepts of one or more aspects in a simplified form as aprelude to the more detailed description that is presented later.

According to an example, a method for communicating in a wirelessnetwork is provided. The method includes receiving, from a networkentity, a resource grant that may include an indicator of whether totransmit a demodulation reference signal (RS) for an uplink controlchannel or an uplink data channel, and determining whether to transmitthe RS in at least one transmission time interval (TTI) based at leastin part on the indicator.

In another example, a user equipment for communicating in a wirelessnetwork is provided. The user equipment includes a transceiver, at leastone processor communicatively coupled with the transceiver via a bus forcommunicating in the wireless network, and a memory communicativelycoupled with the at least one processor and/or the transceiver via thebus. The at least one processor and the memory are operable to receive,from a network entity, a resource grant that may include an indicator ofwhether to transmit a demodulation RS for an uplink control channel oran uplink data channel, and determine whether to transmit the RS in atleast one TTI based at least in part on the indicator.

In another example, a user equipment for communicating in a wirelessnetwork is provided. The user equipment includes means for receiving,from a network entity, a resource grant that may include an indicator ofwhether to transmit a demodulation RS for an uplink control channel oran uplink data channel, and means for determining whether to transmitthe RS in at least one TTI based at least in part on the indicator.

In a further example, a computer-readable storage medium comprisingcomputer-executable code for communicating in a wireless network isprovided. The code includes code for receiving, from a network entity, aresource grant that may include an indicator of whether to transmit ademodulation RS for an uplink control channel or an uplink data channel,and code for determining whether to transmit the RS in at least one TTIbased at least in part on the indicator.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed, and this description is intended to include all suchaspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a block diagram conceptually illustrating an example of atelecommunications system, in accordance with aspects described herein.

FIG. 2 is a diagram illustrating an example of an access network.

FIG. 3 is a diagram illustrating an example of a downlink (DL) framestructure in long term evolution (LTE).

FIG. 4 is a diagram illustrating an example of an uplink (UL) framestructure in LTE.

FIG. 5 is a diagram illustrating an example of a radio protocolarchitecture for the user and control planes.

FIG. 6 is a diagram illustrating an example of an evolved Node B anduser equipment in an access network.

FIG. 7 is a diagram illustrating example timelines for uplink bandwidthallocation.

FIG. 8 is a diagram illustrating an example frame structure for a symbolin a ultra low latency (ULL) LTE system.

FIG. 9 is a diagram illustrating an example frame structure for a symbolin a ULL LTE system.

FIG. 10 is a diagram illustrating example timelines for uplink bandwidthallocation.

FIG. 11 is a diagram illustrating an example frame structure for asymbol in a ULL LTE system.

FIG. 12 is a diagram illustrating an example system for communicatingusing a ULL radio access technology in accordance with aspects describedherein.

FIG. 13 is a diagram illustrating an example method for transmittingcommunications based on a ULL resource grant in accordance with aspectsdescribed herein.

FIG. 14 is a diagram illustrating an example method for generating a ULLresource grant in accordance with aspects described herein.

FIG. 15 is a diagram illustrating an example method for transmitting areference signal in ULL communications in accordance with aspectsdescribed herein.

FIG. 16 is a diagram illustrating an example method for receiving areference signal in ULL communications in accordance with aspectsdescribed herein.

FIG. 17 is a diagram illustrating an example method for transmittingcontrol data in ULL communications in accordance with aspects describedherein.

FIG. 18 is a diagram illustrating an example method for receivingcontrol data in ULL communications in accordance with aspects describedherein.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations and isnot intended to represent the only configurations in which the conceptsdescribed herein may be practiced. The detailed description includesspecific details for the purpose of providing a thorough understandingof various concepts. However, it will be apparent to those skilled inthe art that these concepts may be practiced without these specificdetails. In some instances, well known structures and components areshown in block diagram form in order to avoid obscuring such concepts.

Several aspects of telecommunication systems will now be presented withreference to various apparatus and methods. These apparatus and methodswill be described in the following detailed description and illustratedin the accompanying drawings by various blocks, modules, components,circuits, steps, processes, algorithms, etc. (collectively referred toas “elements”). These elements may be implemented using electronichardware, computer software, or any combination thereof. Whether suchelements are implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem.

By way of example, an element, or any portion of an element, or anycombination of elements may be implemented with a “processing system”that includes one or more processors. Examples of processors includemicroprocessors, microcontrollers, digital signal processors (DSPs),field programmable gate arrays (FPGAs), programmable logic devices(PLDs), state machines, gated logic, discrete hardware circuits, andother suitable hardware configured to perform the various functionalitydescribed throughout this disclosure. One or more processors in theprocessing system may execute software. Software shall be construedbroadly to mean instructions, instruction sets, code, code segments,program code, programs, subprograms, software modules, applications,software applications, software packages, routines, subroutines,objects, executables, threads of execution, procedures, functions, etc.,whether referred to as software, firmware, middleware, microcode,hardware description language, or otherwise.

Accordingly, in one or more aspects, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on or encoded asone or more instructions or code on a computer-readable medium.Computer-readable media includes computer storage media. Storage mediamay be any available media that can be accessed by a computer. By way ofexample, and not limitation, such computer-readable media can compriseRAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic diskstorage or other magnetic storage devices, or any other medium that canbe used to carry or store desired program code in the form ofinstructions or data structures and that can be accessed by a computer.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), and floppy disk where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers. Combinations of the above should also be includedwithin the scope of computer-readable media.

Described herein are various aspects related to communicating in awireless network according to an uplink frame structure of a lowerlatency wireless communication technology that is based on atransmission time interval (TTI) having a duration less than that of alegacy wireless communication technology. In this regard, a lowerlatency in communications is achieved by the shorter, more frequent TTI.For example, where the legacy wireless communication technology is LTE,which has a 1 millisecond (ms) subframe TTI duration, a lower latencywireless communication technology, which is referred to herein as ultralow latency (ULL), may be based on a multiple symbol-level, asymbol-level, or slot-level duration (e.g., a duration that is less thana 1 ms subframe). For a 1 symbol TTI, for example, ULL can achieve alatency that is around 14 times lower than LTE for normal cyclic prefix(CP), and around 12 times lower than LTE for extended CP. It is to beappreciated that CP can relate to a portion of information in a symbolthat is appended to the symbol to allow for determining whether thesymbol is properly received. Normal CP can extend a symbol by around 4.7microseconds (us), and thus results in 7 symbols in a 0.5 ms slot (14symbols in a 1 ms subframe) for LTE communications. Extended CP canextend a symbol by around 16.67 us, and thus results in 6 symbols in a0.5 ms slot (12 symbols in a 1 ms subframe) for LTE communications. Inaddition, a latency related to an amount of time to transmit hybridautomatic repeat/request (HARQ) feedback as part of a HARQ processes inULL is accordingly reduced, as compared to a HARQ latency for LTE, aswell.

In one example, the frame structure for ULL can be designed to coexistwith the legacy wireless communication technology on which the ULL isbased (e.g., at least at a evolved Node B (eNB)). Accordingly, forexample, the frame structure for ULL can be defined within a frequencyband of the legacy wireless communication technology, and/or within adata portion of resources (e.g., excluding a portion of resourcesassigned for control data communication) in the legacy wirelesscommunication technology). Moreover, at least a part of the data portionof resources, in this regard, can be divided into control and datacommunications for ULL, which can further be divided into one or moreresource blocks (RB) groups each comprising a plurality of RBs. Thus, acontrol and data region may also be defined over the RB groups for ULLcommunications. The control channel for ULL can be referred to herein asULL PUCCH (uPUCCH), and the data channel for ULL can be referred toherein as ULL PUSCH (uPUSCH). Moreover, a region for transmission of ULLreference signals (uRS) may also be defined within the data region ofthe legacy wireless communication technology. In addition, where a UEsupports both ULL and the legacy wireless communication technology inthis regard, collision avoidance may be utilized by prioritizing one orboth of the ULL or legacy wireless communication technologycommunications in one or more TTIs where the UE may be assignedconflicting resources for ULL and legacy wireless communications.

Referring first to FIG. 1, a diagram illustrates an example of awireless communications system 100, in accordance with an aspect of thepresent disclosure. The wireless communications system 100 includes aplurality of access points (e.g., base stations, eNBs, or WLAN accesspoints) 105, a number of user equipment (UEs) 115, and a core network130. Access points 105 may include a scheduling component 602 configuredto communicate resource grants to UEs 115 using a ULL frame structure,for example but not limited to frame structure 800 (FIG. 8), framestructure 900 (FIG. 9), frame structure 1100 (FIG. 11), etc., asdescribed herein, which may include a TTI of one symbol (e.g., as shownin timelines 700, 702 in FIG. 7). For example, the ULL frame structuremay include one or both of a uPUCCH and a uPUSCH, respectively.Similarly, one or more of UEs 115 may include a communicating component661 configured to receive, decode, transmit, and operate using the ULLframe structure. Some of the access points 105 may communicate with theUEs 115 under the control of a base station controller (not shown),which may be part of the core network 130 (e.g., wireless network) orthe certain access points 105 (e.g., base stations or eNBs) in variousexamples. Access points 105 may communicate control information and/oruser data with the core network 130 through backhaul links 132. Inexamples, the access points 105 may communicate, either directly orindirectly, with each other over backhaul links 134, which may be wiredor wireless communication links. The wireless communications system 100may support operation on multiple carriers (waveform signals ofdifferent frequencies). Multi-carrier transmitters can transmitmodulated signals simultaneously on the multiple carriers. For example,each communication link 125 may be a multi-carrier signal modulatedaccording to the various radio technologies described above. Eachmodulated signal may be sent on a different carrier and may carrycontrol information (e.g., reference signals (RS), control channels,etc.), overhead information, data, etc.

In some examples, at least a portion of the wireless communicationssystem 100 may be configured to operate on multiple hierarchical layersin which one or more of the UEs 115 and one or more of the access points105 may be configured to support transmissions on a hierarchical layerthat has a reduced latency with respect to another hierarchical layer.In some examples a hybrid UE 115-a may communicate with access point105-a on both a first hierarchical layer that supports first layertransmissions with a first subframe type and a second hierarchical layerthat supports second layer transmissions with a second subframe type.For example, access point 105-a may transmit subframes of the secondsubframe type that are time division duplexed with subframes of thefirst subframe type.

In some examples, hybrid UE 115-a may acknowledge receipt of atransmission by providing an acknowledgement (ACK), or acknowledgereceipt of but inability to properly decode the transmission byproviding a negative-acknowledgement (NACK) for the transmissionthrough, for example, a HARQ scheme. Acknowledgements from hybrid UE115-a for transmissions in the first hierarchical layer may be provided,in some examples, after a predefined number of subframes following thesubframe in which the transmission was received. The hybrid UE 115-a,when operating in the second hierarchical layer may, in examples,acknowledge receipt in a same subframe as the subframe in which thetransmission was received. The time required to transmit an ACK/NACK andreceive a retransmission may be referred to as round trip time (RTT),and thus subframes of the second subframe type may have a second RTTthat is shorter than a RTT for subframes of the first subframe type.

In other examples, a second layer UE 115-b may communicate with accesspoint 105-b on the second hierarchical layer only. Thus, hybrid UE 115-aand second layer UE 115-b may belong to a second class of UEs 115 thatmay communicate on the second hierarchical layer, while legacy UEs 115may belong to a first class of UEs 115 that may communicate on the firsthierarchical layer only. Access point 105-b and UE 115-b may communicateon the second hierarchical layer through transmissions of subframes ofthe second subframe type. Access point 105-b may transmit subframes ofthe second subframe type exclusively, or may transmit one or moresubframes of the first subframe type on the first hierarchical layerthat are time division multiplexed with subframes of the second subframetype. Second layer UE 115-b, in the event that access point 105-btransmits subframes of the first subframe type, may ignore suchsubframes of the first subframe type. Thus, second layer UE 115-b mayacknowledge receipt of transmissions in a same subframe as the subframein which the transmissions are received. Thus, second layer UE 115-b mayoperate with reduced latency compared to UEs 115 that operate on thefirst hierarchical layer.

The access points 105 may wirelessly communicate with the UEs 115 viaone or more access point antennas. Each of the access points 105 sitesmay provide communication coverage for a respective coverage area 110.In some examples, access points 105 may be referred to as a basetransceiver station, a radio base station, a radio transceiver, a basicservice set (BSS), an extended service set (ESS), a NodeB, eNodeB, HomeNodeB, a Home eNodeB, or some other suitable terminology. The coveragearea 110 for a base station may be divided into sectors making up only aportion of the coverage area (not shown). The wireless communicationssystem 100 may include access points 105 of different types (e.g.,macro, micro, and/or pico base stations). The access points 105 may alsoutilize different radio technologies, such as cellular and/or WLAN radioaccess technologies (RAT). The access points 105 may be associated withthe same or different access networks or operator deployments. Thecoverage areas of different access points 105, including the coverageareas of the same or different types of access points 105, utilizing thesame or different radio technologies, and/or belonging to the same ordifferent access networks, may overlap.

In LTE/LTE-A and/or ULL LTE network communication systems, the termsevolved Node B (eNodeB or eNB) may be generally used to describe theaccess points 105. The wireless communications system 100 may be aHeterogeneous LTE/LTE-A/ULL LTE network in which different types ofaccess points provide coverage for various geographical regions. Forexample, each access point 105 may provide communication coverage for amacro cell, a pico cell, a femto cell, and/or other types of cell. Smallcells such as pico cells, femto cells, and/or other types of cells mayinclude low power nodes or LPNs. A macro cell generally covers arelatively large geographic area (e.g., several kilometers in radius)and may allow unrestricted access by UEs 115 with service subscriptionswith the network provider. A small cell would generally cover arelatively smaller geographic area and may allow unrestricted access byUEs 115 with service subscriptions with the network provider, forexample, and in addition to unrestricted access, may also providerestricted access by UEs 115 having an association with the small cell(e.g., UEs in a closed subscriber group (CSG), UEs for users in thehome, and the like). An eNB for a macro cell may be referred to as amacro eNB. An eNB for a small cell may be referred to as a small celleNB. An eNB may support one or multiple (e.g., two, three, four, and thelike) cells.

The core network 130 may communicate with the eNBs or other accesspoints 105 via a backhaul link 132 (e.g., 51 interface, etc.). Theaccess points 105 may also communicate with one another, e.g., directlyor indirectly via backhaul links 134 (e.g., X2 interface, etc.) and/orvia backhaul links 132 (e.g., through core network 130). The wirelesscommunications system 100 may support synchronous or asynchronousoperation. For synchronous operation, the access points 105 may havesimilar frame timing, and transmissions from different access points 105may be approximately aligned in time. For asynchronous operation, theaccess points 105 may have different frame timing, and transmissionsfrom different access points 105 may not be aligned in time.Furthermore, transmissions in the first hierarchical layer and secondhierarchical layer may or may not be synchronized among access points105. The techniques described herein may be used for either synchronousor asynchronous operations.

The UEs 115 are dispersed throughout the wireless communications system100, and each UE 115 may be stationary or mobile. A UE 115 may also bereferred to by those skilled in the art as a mobile station, asubscriber station, a mobile unit, a subscriber unit, a wireless unit, aremote unit, a mobile device, a wireless device, a wirelesscommunications device, a remote device, a mobile subscriber station, anaccess terminal, a mobile terminal, a wireless terminal, a remoteterminal, a handset, a user agent, a mobile client, a client, or someother suitable terminology. A UE 115 may be a cellular phone, a personaldigital assistant (PDA), a wireless modem, a wireless communicationdevice, a handheld device, a tablet computer, a laptop computer, acordless phone, a wearable item such as a watch or glasses, a wirelesslocal loop (WLL) station, or the like. A UE 115 may be able tocommunicate with macro eNodeBs, small cell eNodeBs, relays, and thelike. A UE 115 may also be able to communicate over different accessnetworks, such as cellular or other WWAN access networks, or WLAN accessnetworks.

The communication links 125 shown in wireless communications system 100may include uplink (UL) transmissions from a UE 115 to an access point105, and/or downlink (DL) transmissions, from an access point 105 to aUE 115. The downlink transmissions may also be called forward linktransmissions while the uplink transmissions may also be called reverselink transmissions. The communication links 125 may carry transmissionsof each hierarchical layer which, in some examples, may be multiplexedin the communication links 125. The UEs 115 may be configured tocollaboratively communicate with multiple access points 105 through, forexample, Multiple Input Multiple Output (MIMO), carrier aggregation(CA), Coordinated Multi-Point (CoMP), or other schemes. MIMO techniquesuse multiple antennas on the access points 105 and/or multiple antennason the UEs 115 to transmit multiple data streams. Carrier aggregationmay utilize two or more component carriers on a same or differentserving cell for data transmission. CoMP may include techniques forcoordination of transmission and reception by a number of access points105 to improve overall transmission quality for UEs 115 as well asincreasing network and spectrum utilization.

As mentioned, in some examples access points 105 and UEs 115 may utilizecarrier aggregation to transmit on multiple carriers. In some examples,access points 105 and UEs 115 may concurrently transmit in a firsthierarchical layer, within a frame, one or more subframes each having afirst subframe type using two or more separate carriers. Each carriermay have a bandwidth of, for example, 20 MHz, although other bandwidthsmay be utilized. Hybrid UE 115-a, and/or second layer UE 115-b may, incertain examples, receive and/or transmit one or more subframes in asecond hierarchical layer utilizing a single carrier that has abandwidth greater than a bandwidth of one or more of the separatecarriers. For example, if four separate 20 MHz carriers are used in acarrier aggregation scheme in the first hierarchical layer, a single 80MHz carrier may be used in the second hierarchical layer. The 80 MHzcarrier may occupy a portion of the radio frequency spectrum that atleast partially overlaps the radio frequency spectrum used by one ormore of the four 20 MHz carriers. In some examples, scalable bandwidthfor the second hierarchical layer type may be combined techniques toprovide shorter RTTs such as described above, to provide furtherenhanced data rates.

Each of the different operating modes that may be employed by wirelesscommunications system 100 may operate according to frequency divisionduplexing (FDD) or time division duplexing (TDD). In some examples,different hierarchical layers may operate according to different TDD orFDD modes. For example, a first hierarchical layer may operate accordingto FDD while a second hierarchical layer may operate according to TDD.In some examples, OFDMA communications signals may be used in thecommunication links 125 for LTE downlink transmissions for eachhierarchical layer, while single carrier frequency division multipleaccess (SC-FDMA) communications signals may be used in the communicationlinks 125 for LTE uplink transmissions in each hierarchical layer.Additional details regarding implementation of hierarchical layers in asystem such as the wireless communications system 100, as well as otherfeatures and functions related to communications in such systems, areprovided below with reference to the following figures.

FIG. 2 is a diagram illustrating an example of an access network 200 inan LTE or ULL LTE network architecture. In this example, the accessnetwork 200 is divided into a number of cellular regions (cells) 202.One or more lower power class eNBs 208 may have cellular regions 210that overlap with one or more of the cells 202. The lower power classeNB 208 may be a femto cell (e.g., home eNB (HeNB)), pico cell, microcell, or remote radio head (RRH). The macro eNBs 204 are each assignedto a respective cell 202 and are configured to provide an access pointto the core network 130 for all the UEs 206 in the cells 202. In anaspect, eNBs 204 may include a scheduling component 602 configured tocommunicate resource grants to UEs 206 using a ULL frame structure, forexample but not limited to frame structure 800 (FIG. 8), frame structure900 (FIG. 9), frame structure 1100 (FIG. 11), etc., which may include aTTI of one symbol (e.g., as shown in timelines 700, 702 in FIG. 7).Similarly, one or more of UEs 206 may include a communicating component661 configured to receive, decode, transmit, and operate using the ULLframe structure. There is no centralized controller in this example ofan access network 200, but a centralized controller may be used inalternative configurations. The eNBs 204 are responsible for all radiorelated functions including radio bearer control, admission control,mobility control, scheduling, security, and connectivity to a servinggateway.

The modulation and multiple access scheme employed by the access network200 may vary depending on the particular telecommunications standardbeing deployed. In LTE or ULL LTE applications, OFDM may be used on theDL and SC-FDMA may be used on the UL to support both frequency divisionduplexing (FDD) and time division duplexing (TDD). As those skilled inthe art will readily appreciate from the detailed description to follow,the various concepts presented herein are well suited for LTEapplications. However, these concepts may be readily extended to othertelecommunication standards employing other modulation and multipleaccess techniques. By way of example, these concepts may be extended toEvolution-Data Optimized (EV-DO) or Ultra Mobile Broadband (UMB). EV-DOand UMB are air interface standards promulgated by the 3rd GenerationPartnership Project 2 (3GPP2) as part of the CDMA2000 family ofstandards and employs CDMA to provide broadband Internet access tomobile stations. These concepts may also be extended to UniversalTerrestrial Radio Access (UTRA) employing Wideband-CDMA (W-CDMA) andother variants of CDMA, such as TD-SCDMA; Global System for MobileCommunications (GSM) employing TDMA; and Evolved UTRA (E-UTRA), IEEE802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, and Flash-OFDMemploying OFDMA. UTRA, E-UTRA, UMTS, LTE and GSM are described indocuments from the 3GPP organization. CDMA2000 and UMB are described indocuments from the 3GPP2 organization. The actual wireless communicationstandard and the multiple access technology employed will depend on thespecific application and the overall design constraints imposed on thesystem.

The eNBs 204 may have multiple antennas supporting MIMO technology. Theuse of MIMO technology enables the eNBs 204 to exploit the spatialdomain to support spatial multiplexing, beamforming, and transmitdiversity. Spatial multiplexing may be used to transmit differentstreams of data simultaneously on the same frequency. The data steamsmay be transmitted to a single UE 206 to increase the data rate or tomultiple UEs 206 to increase the overall system capacity. This isachieved by spatially precoding each data stream (i.e., applying ascaling of an amplitude and a phase) and then transmitting eachspatially precoded stream through multiple transmit antennas on the DL.The spatially precoded data streams arrive at the UE(s) 206 withdifferent spatial signatures, which enables each of the UE(s) 206 torecover the one or more data streams destined for that UE 206. On theUL, each UE 206 transmits a spatially precoded data stream, whichenables the eNB 204 to identify the source of each spatially precodeddata stream.

Spatial multiplexing is generally used when channel conditions are good.When channel conditions are less favorable, beamforming may be used tofocus the transmission energy in one or more directions. This may beachieved by spatially precoding the data for transmission throughmultiple antennas. To achieve good coverage at the edges of the cell, asingle stream beamforming transmission may be used in combination withtransmit diversity.

In the detailed description that follows, various aspects of an accessnetwork will be described with reference to a MIMO system supportingOFDM on the DL. OFDM is a spread-spectrum technique that modulates dataover a number of subcarriers within an OFDM symbol. The subcarriers arespaced apart at precise frequencies. The spacing provides“orthogonality” that enables a receiver to recover the data from thesubcarriers. In the time domain, a guard interval (e.g., cyclic prefix)may be added to each OFDM symbol to combat inter-OFDM-symbolinterference. The UL may use SC-FDMA in the form of a discrete Fouriertransform (DFT)-spread OFDM signal to compensate for highpeak-to-average power ratio (PAPR).

FIG. 3 is a diagram 300 illustrating an example of a DL frame structurein LTE. A frame (10 ms) may be divided into 10 equally sized sub-frames.Each sub-frame may include two consecutive time slots. A resource gridmay be used to represent two time slots, each time slot including aresource element block (also referred to herein as a RB). The resourcegrid is divided into multiple resource elements. In LTE, a resourceelement block may contain 12 consecutive subcarriers in the frequencydomain and, for a normal cyclic prefix in each OFDM symbol, 7consecutive OFDM symbols in the time domain, or 84 resource elements.For an extended cyclic prefix, a resource element block may contain 6consecutive OFDM symbols in the time domain and has 72 resourceelements. Some of the resource elements, as indicated as R 302, 304,include DL reference signals (DL-RS). The DL-RS include Cell-specific RS(CRS) (also sometimes called common RS) 302 and UE-specific RS (UE-RS)304. UE-RS 304 are transmitted only on the resource element blocks uponwhich the corresponding PDSCH is mapped. The number of bits carried byeach resource element depends on the modulation scheme. Thus, the moreresource element blocks that a UE receives and the higher the modulationscheme, the higher the data rate for the UE.

FIG. 4 is a diagram 400 illustrating an example of an UL frame structurein LTE, which, in some examples, may be utilized in conjunction with theULL LTE UL frame structure described herein. The available resourceelement blocks for the UL may be partitioned into a data section and acontrol section. The control section may be formed at the two edges ofthe system bandwidth and may have a configurable size. The resourceelement blocks in the control section may be assigned to UEs fortransmission of control information. The data section may include allresource element blocks not included in the control section. The ULframe structure results in the data section including contiguoussubcarriers, which may allow a single UE to be assigned all of thecontiguous subcarriers in the data section.

A UE may be assigned resource element blocks 410 a, 410 b in the controlsection to transmit control information to an eNB. The UE may also beassigned resource element blocks 420 a, 420 b in the data section totransmit data to the eNB. The UE may transmit control information in aphysical UL control channel (PUCCH) on the assigned resource elementblocks in the control section. The UE may transmit only data or bothdata and control information in a physical UL shared channel (PUSCH) onthe assigned resource element blocks in the data section. A ULtransmission may span both slots of a subframe and may hop acrossfrequency.

A set of resource element blocks may be used to perform initial systemaccess and achieve UL synchronization in a physical random accesschannel (PRACH) 430. The PRACH 430 carries a random sequence and cannotcarry any UL data/signaling. Each random access preamble occupies abandwidth corresponding to six consecutive resource element blocks. Thestarting frequency is specified by the network. That is, thetransmission of the random access preamble is restricted to certain timeand frequency resources. There is no frequency hopping for the PRACH.The PRACH attempt is carried in a single subframe (1 ms) or in asequence of few contiguous subframes and a UE can make only a singlePRACH attempt per frame (10 ms).

FIG. 5 is a diagram 500 illustrating an example of a radio protocolarchitecture for the user and control planes in LTE and ULL LTE. Theradio protocol architecture for the UE and the eNB is shown with threelayers: Layer 1, Layer 2, and Layer 3. Layer 1 (L1 layer) is the lowestlayer and implements various physical layer signal processing functions.The L1 layer will be referred to herein as the physical layer 506. Layer2 (L2 layer) 508 is above the physical layer 506 and is responsible forthe link between the UE and eNB over the physical layer 506.

In the user plane, the L2 layer 508 includes a media access control(MAC) sublayer 510, a radio link control (RLC) sublayer 512, and apacket data convergence protocol (PDCP) 514 sublayer, which areterminated at the eNB on the network side. Although not shown, the UEmay have several upper layers above the L2 layer 508 including a networklayer (e.g., IP layer) that is terminated at a PDN gateway on thenetwork side, and an application layer that is terminated at the otherend of the connection (e.g., far end UE, server, etc.).

The PDCP sublayer 514 provides multiplexing between different radiobearers and logical channels. The PDCP sublayer 514 also provides headercompression for upper layer data packets to reduce radio transmissionoverhead, security by ciphering the data packets, and handover supportfor UEs between eNBs. The RLC sublayer 512 provides segmentation andreassembly of upper layer data packets, retransmission of lost datapackets, and reordering of data packets to compensate for out-of-orderreception due to hybrid automatic repeat request (HARQ). The MACsublayer 510 provides multiplexing between logical and transportchannels. The MAC sublayer 510 is also responsible for allocating thevarious radio resources (e.g., resource element blocks) in one cellamong the UEs. The MAC sublayer 510 is also responsible for HARQoperations.

In the control plane, the radio protocol architecture for the UE and eNBis substantially the same for the physical layer 506 and the L2 layer508 with the exception that there is no header compression function forthe control plane. The control plane also includes a radio resourcecontrol (RRC) sublayer 516 in Layer 3 (L3 layer). The RRC sublayer 516is responsible for obtaining radio resources (i.e., radio bearers) andfor configuring the lower layers using RRC signaling between the eNB andthe UE.

FIG. 6 is a block diagram of an eNB 610 in communication with a UE 650in an access network. In the DL, upper layer packets from the corenetwork are provided to a controller/processor 675. Thecontroller/processor 675 implements the functionality of the L2 layer.In the DL, the controller/processor 675 provides header compression,ciphering, packet segmentation and reordering, multiplexing betweenlogical and transport channels, and radio resource allocations to the UE650 based on various priority metrics. The controller/processor 675 isalso responsible for HARQ operations, retransmission of lost packets,and signaling to the UE 650.

The transmit (TX) processor 616 implements various signal processingfunctions for the L1 layer (i.e., physical layer). The signal processingfunctions includes coding and interleaving to facilitate forward errorcorrection (FEC) at the UE 650 and mapping to signal constellationsbased on various modulation schemes (e.g., binary phase-shift keying(BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying(M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded andmodulated symbols are then split into parallel streams. Each stream isthen mapped to an OFDM subcarrier, multiplexed with a reference signal(e.g., pilot) in the time and/or frequency domain, and then combinedtogether using an Inverse Fast Fourier Transform (IFFT) to produce aphysical channel carrying a time domain OFDM symbol stream. The OFDMstream is spatially precoded to produce multiple spatial streams.Channel estimates from a channel estimator 674 may be used to determinethe coding and modulation scheme, as well as for spatial processing. Thechannel estimate may be derived from a reference signal and/or channelcondition feedback transmitted by the UE 650. Each spatial stream isthen provided to a different antenna 620 via a separate transmitter618TX. Each transmitter 618TX modulates an RF carrier with a respectivespatial stream for transmission. In addition, eNB 610 may include ascheduling component 602 configured to communicate resource grants to UE650 using a ULL frame structure, for example but not limited to framestructure 800 (FIG. 8), frame structure 900 (FIG. 9), frame structure1100 (FIG. 11), etc., which may include a TTI of one symbol (e.g., asshown in timelines 700, 702 in FIG. 7). Though scheduling component 602is shown as coupled to controller/processor 675, it is to be appreciatedthat scheduling component 602 can also be coupled to other processors(e.g., RX processor 670, TX processor 616, etc.) and/or implemented bythe one or more processors 616, 670, 675 to perform actions describedherein

At the UE 650, each receiver 654RX receives a signal through itsrespective antenna 652. Each receiver 654RX recovers informationmodulated onto an RF carrier and provides the information to the receive(RX) processor 656. The RX processor 656 implements various signalprocessing functions of the L1 layer. The RX processor 656 performsspatial processing on the information to recover any spatial streamsdestined for the UE 650. If multiple spatial streams are destined forthe UE 650, they may be combined by the RX processor 656 into a singleOFDM symbol stream. The RX processor 656 then converts the OFDM symbolstream from the time-domain to the frequency domain using a Fast FourierTransform (FFT). The frequency domain signal comprises a separate OFDMsymbol stream for each subcarrier of the OFDM signal. The symbols oneach subcarrier, and the reference signal, is recovered and demodulatedby determining the most likely signal constellation points transmittedby the eNB 610. These soft decisions may be based on channel estimatescomputed by the channel estimator 658. The soft decisions are thendecoded and deinterleaved to recover the data and control signals thatwere originally transmitted by the eNB 610 on the physical channel. Thedata and control signals are then provided to the controller/processor659.

The controller/processor 659 implements the L2 layer. Thecontroller/processor can be associated with a memory 660 that storesprogram codes and data. The memory 660 may be referred to as acomputer-readable medium. In the UL, the controller/processor 659provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, control signal processingto recover upper layer packets from the core network. The upper layerpackets are then provided to a data sink 662, which represents all theprotocol layers above the L2 layer. Various control signals may also beprovided to the data sink 662 for L3 processing. Thecontroller/processor 659 is also responsible for error detection usingan acknowledgement (ACK) and/or negative acknowledgement (NACK) protocolto support HARQ operations. In addition, UE 650 may include acommunicating component 661 configured to receive, decode, transmit, andoperate using the ULL frame structure, as described herein. Thoughcommunicating component 661 is shown as coupled to controller/processor659, it is to be appreciated that communicating component 661 can alsobe coupled to other processors (e.g., RX processor 656, TX processor668, etc.) and/or implemented by the one or more processors 656, 659,668 to perform actions described herein

In the UL, a data source 667 is used to provide upper layer packets tothe controller/processor 659. The data source 667 represents allprotocol layers above the L2 layer. Similar to the functionalitydescribed in connection with the DL transmission by the eNB 610, thecontroller/processor 659 implements the L2 layer for the user plane andthe control plane by providing header compression, ciphering, packetsegmentation and reordering, and multiplexing between logical andtransport channels based on radio resource allocations by the eNB 610.The controller/processor 659 is also responsible for HARQ operations,retransmission of lost packets, and signaling to the eNB 610.

Channel estimates derived by a channel estimator 658 from a referencesignal or feedback transmitted by the eNB 610 may be used by the TXprocessor 668 to select the appropriate coding and modulation schemes,and to facilitate spatial processing. The spatial streams generated bythe TX processor 668 are provided to different antenna 652 via separatetransmitters 654TX. Each transmitter 654TX modulates an RF carrier witha respective spatial stream for transmission.

The UL transmission is processed at the eNB 610 in a manner similar tothat described in connection with the receiver function at the UE 650.Each receiver 618RX receives a signal through its respective antenna620. Each receiver 618RX recovers information modulated onto an RFcarrier and provides the information to a RX processor 670. The RXprocessor 670 may implement the L1 layer.

The controller/processor 675 implements the L2 layer. Thecontroller/processor 675 can be associated with a memory 676 that storesprogram codes and data. The memory 676 may be referred to as acomputer-readable medium. In the UL, the controller/processor 675provides demultiplexing between transport and logical channels, packetreassembly, deciphering, header decompression, control signal processingto recover upper layer packets from the UE 650. Upper layer packets fromthe controller/processor 675 may be provided to the core network. Thecontroller/processor 675 is also responsible for error detection usingan ACK and/or NACK protocol to support HARQ operations.

FIG. 7 is a diagram illustrating non-limiting examples of a ULLtimelines 700, 702, with time extending from left to right in thefigure, for managing ULL communications in a wireless communicationsystem. In this example, timelines 700, 702 include ULL frames of symbolduration in each symbol of a subframe. Timelines 700, 702 both depictsymbols representing a TTI for ULL physical downlink control channel(uPDCCH) and/or ULL physical downlink shared channel (uPDSCH) andsymbols representing a TTI including uPUCCH and/or uPDSCH. In timelines700, 14 symbols 710, 711, etc. are shown within a given subframe 712(e.g., for normal CP), and in timelines 702, 12 symbols 720, 721, etc.are shown within a given subframe 722 (e.g., for extended CP). In eithercase, lower latency is achieved in ULL by utilizing symbol-based TTIs(as opposed to subframe-based TTIs in LTE). It is to be appreciated, inother examples, that a TTI may be two or more symbols, a slot of asubframe (where a subframe includes two slots), etc. In addition, HARQprocess response time can be on the order of a number of symbols (e.g.,3 symbols, 4 symbols, etc.), a number of sets of symbols (e.g., 3dual-symbols, 4 dual-symbols, etc.) a number of slots (e.g., 3 slots, 4slots, etc.), based on the duration of the TTI for ULL communications.In the depicted example, ULL communications are 1 symbol in duration,uPDCCH/uPDSCH is sent in symbol 0, and HARQ is processed and is sent insymbol 4, etc. in the subframe. Thus, an amount of time associated withthe HARQ latency in ULL communications is less than a corresponding HARQlatency in LTE communications as well based on the shortened TTIduration.

FIG. 8 illustrates an example frame structure 800 for ULL LTE (and/orLTE) communications. For example, as described, frame structure 800 canrepresent a symbol duration TTI (e.g., of an OFDM, SC-FDM, or similarsymbol, such as a symbol 710, 711, 720, 721, etc. in FIG. 7), a two ormore symbol duration TTI, a slot duration TTI, etc., which isrepresented vertically in frequency (and horizontally in time, asdescribed). In any case, the frame structure for ULL can be definedwithin a current LTE UL frame structure. For example, frame structure800 includes PUCCH regions 802 of LTE at the ends of the frame (e.g., inuplink frequency bandwidth), which are undisturbed by the ULL LTE framestructure, in this example. Rather, the ULL frame structure is definedwithin the PUSCH region 804 in LTE.

As shown in this example, at least some of the LTE PUSCH region 806 isoptionally maintained in the LTE PUSCH region 804, and uPUCCH regions808 and a uPUSCH region 810 are also included in the LTE PUSCH region804. In this example frame structure 800, the uPUCCH regions 808 aresimilarly at the ends of the LTE PUSCH region 804 that is usable forULL. A remainder of the LTE PUSCH region 804 can be divided into thePUSCH region 806 and the uPUSCH region 810 (e.g., based on scheduling byan eNB or other network node). It is to be appreciated thatsubstantially any frame structure may be employed such that LTE and ULLcan coexist in a given TTI. Moreover, as described further herein forexample, an eNB can allocate resources to one or more UEs according tothe regions in the frame structure 800 (and can thus support LTE and/orULL communications), and a receiving UE may be somewhat agnostic to theframe structure by using resources as allocated to the UE by the eNB.

FIG. 9 illustrates an example frame structure 900 for ULL (and/or LTE)communications. For example, as described, frame structure 900 canrepresent a symbol duration TTI (e.g., of an OFDM, SC-FDM, or similarsymbol, such as a symbol 710, 711, 720, 721, etc. in FIG. 7), a two ormore symbol duration TTI, a slot duration TTI, etc., which isrepresented vertically in frequency (and horizontally in time, asdescribed). In any case, as described, the frame structure for ULL canbe defined within a current LTE UL frame structure. For example, framestructure 900 includes PUCCH regions 802 of LTE at the ends of theframe, which are undisturbed by the ULL LTE frame structure, in thisexample. Rather, the ULL frame structure is defined within the PUSCHregion 804 in LTE.

In this example, the RBs usable for ULL can be defined as the total RBsavailable for UL communications in the TTI (N_(RB) ^(UL)) minus anoffset (N_(RB) ^(Offset)), where N_(RB) ^(Offset) can be intended toaccommodate the combined size of PUCCH regions 802 in LTE and possibly auPUCCH region in ULL LTE. The RBs usable for ULL communications can befurther divided into a number of RB groups, such as RB group 902, whichmay be contiguous in frequency and may include a number of RBs, such asRB 904. In this example, 4 RB groups of 14 RBs are shown (e.g., muchlike LTE, but the RBs are divided within a symbol duration, two or moresymbol duration, slot duration, etc., instead of a subframe duration).uPUCCH and/or uPUSCH communications can accordingly be scheduled overthe RBs in the RB groups (e.g., according to frame structure 800).

In one example, each RB group 902 can include a multiple of 2, 3, 5,etc. RBs where each group can be equal in number of RBs or not. Forinstance, the number of RBs in the RB group(s) can be based on aconfigured starting offset (N_(RB) ^(Offset)), the uPUSCH bandwidthdetermined for the TTI, and/or the like. One specific example of RBgroup sizes to achieve certain system bandwidths can be the following:

uPUSCH Bandwidth (RBs) RB Group Sizes 96 {24, 24, 24, 24} 88 {20, 20,24, 24} 80 {20, 20, 20, 20} 72 {18, 18, 18, 18} 64 {16, 16, 16, 16} 56{12, 12, 16, 16} 48 {24, 24} 40 {20. 20} 32 {16, 16} 24 {24} 16 {16} 12{12}In addition, for example, the number of RBs can be similar for certainsymbol types (e.g., symbols that do not include a sounding referencesignal (SRS) (also referred to herein as “non-SRS symbols”)), butsymbols of a symbol type that do include an SRS (also referred to hereinas “SRS symbols”) may have a number of RBs associated with specific SRSbandwidth. For example, current LTE cell-specific SRS bandwidth may bethe following for 5/10/15/20 megahertz (MHz): 5 MHz supports36/32/24/20/16/12/8/4 RBs for SRS, 10 MHz supports 48/40/36/32/24/20/16RBs for SRS, 15 MHz supports 72/64/60/48/40/36/32 RBs for SRS, and 20MHz supports 96/80/72/64/60/48 RBs for cell-specific SRS. In addition,in an example, the number of RBs and/or RB groups for uPUSCH can beaccordingly adjusted based in part on the bandwidth for the SRS in ULLwhere the uPUSCH includes a cell-specific SRS. Note that for the caseswhen the cell-specific SRS bandwidth is small (e.g., 4 RBs or 8 RBs),uPUSCH transmissions may or may not be supported in SRS symbols.Alternatively, in such cases, uPUSCH may be supported but may not followthe RB group management as in non-SRS symbols. For example, if thecell-specific SRS bandwidth is 16 RBs in a 100 RB uplink bandwidth,uPUSCH may be assigned by excluding the 16 RB cell-specific SRSbandwidth, and dividing the remaining 84 RBs into 4 groups. As anotherexample, if the cell-specific SRS bandwidth is 16 RBs in a 100 RB uplinkbandwidth, uPUSCH may be assigned by using the 16 RB as a group, anddividing the remaining 84 RBs into 3 other groups.

In any case, an eNB can assign resources to one or more UEs according tothe determined bandwidth for uPUSCH based on a corresponding number ofRBs in one or more RB groups within the TTI using the frame structures800 and/or 900 shown above.

FIG. 10 illustrates example timelines 1000, 1010 for RS transmission inULL communications. Timeline 1000 includes transmission of uPUCCH/uPUSCH1004 in ULL frames that are of a symbol duration in an LTE subframe. Inaddition, ULL RS (also referred to as uRS) transmissions 1002 aredepicted in timeline 1000 at different symbols. It is to be appreciated,as described, that transmission of uRS for a given UE can occur withouttransmission of uPUCCH and/or uPUSCH. In timeline 1000, transmission ofuRS can be periodic (e.g., every 6 then 9 symbols), though transmissionmay be aperiodic as well. In either case, as described further below,triggering of uRS transmission can be specified by the eNB (e.g., in oneor more resource grants to the UE or otherwise, as described herein).

Timeline 1010 depicts an uplink grant received at symbol 1012, which canspecify a uRS transmission in symbol 1014 and uPUSCH transmission insymbol 1016. Transmission of uRS can be aperiodic, in this example, suchthat the uplink grant triggers transmission of the uRS (and thus uRS isbased on receiving the uplink grant and not necessarily on a certainperiod). In one example, transmission of uRS in symbol 1014 can beassociated with transmission of uPUSCH in symbol 1016. For example,where resource grant in symbol 1012 specifies uPUSCH transmission insymbol 1016 and a uRS trigger, the UE can determine to transmit uRS inthe preceding symbol 1014 based on receiving a uRS trigger in the grant.In this regard, for example, the trigger may specify a number of symbols(or more generally, TTIs) before the symbol related to the uplinkresource grant for transmitting the uRS. Although not shown, the same UEmay be scheduled with another uPUSCH transmission without uRS beingtriggered, e.g., the symbol right after symbol 1016. In this case, thisuPUSCH transmission can rely on uRS in symbol 1012 for demodulation.Although not shown, it is also possible to schedule uRS transmission inone or more symbols without the accompanying uPUSCH or uPUCCH.

FIG. 11 illustrates an example frame structure 1100 for ULLcommunications. For example, as described, frame structure 1100 canrepresent a symbol duration TTI (e.g., of an OFDM, SC-FDM, or similarsymbol), a two or more symbol duration TTI, a slot duration TTI, etc. Inany case, frame structure 1100 can be defined within a current LTE ULframe structure, and may be similar to frame structure 800 (FIG. 8). Forexample, frame structure 1100 includes PUCCH regions 802 at the ends ofthe frame, which are undisturbed by the ULL frame structure, in thisexample. Rather, the ULL frame structure is defined within the PUSCHregion 804 in LTE. Thus, as shown, a PUSCH region 806 is optionallymaintained in the LTE PUSCH region 804, and uPUCCH regions 808 and auPUSCH region 810 are also included. In this example frame structure1100, the uPUCCH regions 808 are similarly at the ends of the LTE PUSCHregion 804 that is usable for ULL. A remainder of the LTE PUSCH region804 is divided into the PUSCH region 806 and the uPUSCH region 810.

In addition, uRS regions 1102 are defined within the uPUCCH regions 808and the uPUSCH regions 810 for transmitting uRS based on a receivedtrigger, as described further herein. Additionally, in this regard, uRScan be transmitted for both uPUCCH and uPUSCH (e.g., uRS for uPUCCH canbe a DM-RS to assist in demodulating communications over the uPUCCH, anduRS for uPUSCH can be a DM-RS to assist in demodulating communicationsover the uPUSCH). uRS for uPUCCH may be narrowband and in a semi-staticfrequency location, as depicted in the uRS regions 1102 in uPUCCHregions 808, while uRS for PUSCH may be wideband and potentially indynamic frequency locations, as depicted in the uRS regions 1102 in theuPUSCH region 810. In this regard, the uRS may have at least one of abandwidth size, a frequency location, a number of antenna ports, etc.consistent with that of uPUCCH or uPUSCH. It is to be appreciated thatsubstantially any frame structure may be employed such that LTE and ULLcan coexist in a given TTI. Moreover, as described further herein forexample, an eNB can allocate resources according to the frame structure1100 (and can thus support LTE and/or ULL communications), and areceiving UE may be somewhat agnostic to the frame structure by usingresources as allocated by the eNB.

Referring to FIGS. 12-18, aspects are depicted with reference to one ormore components and one or more methods that may perform the actions orfunctions described herein. In an aspect, the term “component” as usedherein may be one of the parts that make up a system, may be hardware orsoftware or some combination thereof, and may be divided into othercomponents. Although the operations described below in FIGS. 13-18 arepresented in a particular order and/or as being performed by an examplecomponent, it should be understood that the ordering of the actions andthe components performing the actions may be varied, depending on theimplementation. Moreover, it should be understood that the followingactions or functions may be performed by a specially-programmedprocessor, a processor executing specially-programmed software orcomputer-readable media, or by any other combination of a hardwarecomponent and/or a software component capable of performing thedescribed actions or functions.

FIG. 12 illustrates an example system 1200 for communicating in awireless network using ULL. System 1200 includes a UE 1202 thatcommunicates with an eNB 1204 to access a wireless network, examples ofwhich are described in FIGS. 1, 2, 6, etc., above. UE 1202 cancommunicate with a wireless network (e.g., core network 130) via eNB1204. In an aspect, eNB 1204 and UE 1202 may have established one ormore downlink channels over which downlink signals 1209 can betransmitted by eNB 1204 (e.g., via transceiver 1256) and received by UE1202 (e.g., via transceiver 1206) for communicating control and/or datamessages (e.g., signaling) from the eNB 1204 to the UE 1202 overconfigured communication resources. Moreover, for example, eNB 1204 andUE 1202 may have established one or more uplink channels over whichuplink signals 1208 can be transmitted by UE 1202 (e.g., via transceiver1206) and received by eNB 1204 (e.g., via transceiver 1256) forcommunicating control and/or data messages (e.g., signaling) from the UE1202 to the eNB 1204 over configured communication resources. Forexample, eNB 1204 may communicate uplink resource grants 1280 to the UE1202, which can indicate resources over which the UE 1202 can transmitULL and/or LTE communications 1282 to the eNB 1204 (e.g., along withrelated control data, reference signals, etc.), as described herein.

In an aspect, UE 1202 may include one or more processors 1203 and/or amemory 1205 that may be communicatively coupled, e.g., via one or morebuses 1207, and may operate in conjunction with or otherwise implement acommunicating component 661 for receiving and transmitting ULLcommunications with one or more eNBs or other network nodes, asdescribed herein, which may include receiving ULL resource grants fromeNB 1204 for downlink or uplink ULL channels and communicating over theULL resources. For example, the various operations related tocommunicating component 661 may be implemented or otherwise executed byone or more processors 1203 and, in an aspect, can be executed by asingle processor, while in other aspects, different ones of theoperations may be executed by a combination of two or more differentprocessors. For example, in an aspect, the one or more processors 1203may include any one or any combination of a modem processor, or abaseband processor, or a digital signal processor, or an applicationspecific integrated circuit (ASIC), or a transmit processor, receiveprocessor, or a transceiver processor associated with transceiver 1206.Further, for example, the memory 1205 may be a non-transitorycomputer-readable medium that includes, but is not limited to, randomaccess memory (RAM), read only memory (ROM), programmable ROM (PROM),erasable PROM (EPROM), electrically erasable PROM (EEPROM), a magneticstorage device (e.g., hard disk, floppy disk, magnetic strip), anoptical disk (e.g., compact disk (CD), digital versatile disk (DVD)), asmart card, a flash memory device (e.g., card, stick, key drive), aregister, a removable disk, and any other suitable medium for storingsoftware and/or computer-readable code or instructions that may beaccessed and read by a computer or one or more processors 1203.Moreover, memory 1205 or computer-readable storage medium may beresident in the one or more processors 1203, external to the one or moreprocessors 1203, distributed across multiple entities including the oneor more processors 1203, etc.

In particular, the one or more processors 1203 and/or memory 1205 mayexecute actions or operations defined by communicating component 661 orits subcomponents. For instance, the one or more processors 1203 and/ormemory 1205 may execute actions or operations defined by a resourcegrant receiving component 1210 for obtaining resource grants from eNB1204. In an aspect, for example, resource grant receiving component 1210may include hardware (e.g., one or more processor modules of the one ormore processors 1203) and/or computer-readable code or instructionsstored in memory 1205 and executable by at least one of the one or moreprocessors 1203 to perform the specially configured resource grantreceiving and/or processing operations described herein. Further, forinstance, the one or more processors 1203 and/or memory 1205 may executeactions or operations defined by a TTI determining component 1212 fordetermining a TTI associated with the resource grants. In an aspect, forexample, TTI determining component 1212 may include hardware (e.g., oneor more processor modules of the one or more processors 1203) and/orcomputer-readable code or instructions stored in memory 1205 andexecutable by at least one of the one or more processors 1203 to performthe specially configured TTI determining described herein. Further, forinstance, the one or more processors 1203 and/or memory 1205 mayoptionally execute actions or operations defined by an optionaltransport block size (TBS) determining component 1214 for determining aTBS, TBS scaling factor, and/or the like for transmitting communicationsover the granted resources. In an aspect, for example, TBS determiningcomponent 1214 may include hardware (e.g., one or more processor modulesof the one or more processors 1203) and/or computer-readable code orinstructions stored in memory 1205 and executable by at least one of theone or more processors 1203 to perform the specially configured TBSdetermining operations described herein. Further, for instance, the oneor more processors 1203 and/or memory 1205 may optionally executeactions or operations defined by an optional communication prioritizingcomponent 1216 for determining whether to prioritize ULL communicationsor communications over a legacy wireless technology. In an aspect, forexample, communication prioritizing component 1216 may include hardware(e.g., one or more processor modules of the one or more processors 1203)and/or computer-readable code or instructions stored in memory 1205 andexecutable by at least one of the one or more processors 1203 to performthe specially configured communication prioritizing operations describedherein. Further, for instance, the one or more processors 1203 and/ormemory 1205 may optionally execute actions or operations defined by anoptional RS trigger receiving component 1218 for obtaining a trigger totransmit one or more RSs. In an aspect, for example, RS triggerreceiving component 1218 may include hardware (e.g., one or moreprocessor modules of the one or more processors 1203) and/orcomputer-readable code or instructions stored in memory 1205 andexecutable by at least one of the one or more processors 1203 to performthe specially configured RS triggering operations described herein.

Similarly, in an aspect, eNB 1204 may include one or more processors1253 and/or a memory 1255 that may be communicatively coupled, e.g., viaone or more buses 1257, and may operate in conjunction with or otherwiseimplement a one or more of a scheduling component 602 for communicatingwith a UE 1202 over assigned ULL resources, as described herein, whichmay include providing the resource grants for UE 1202 and/or other UEsaccording to the ULL resources. For example, the various functionsrelated to scheduling component 602 may be implemented or otherwiseexecuted by one or more processors 1253 and, in an aspect, can beexecuted by a single processor, while in other aspects, different onesof the functions may be executed by a combination of two or moredifferent processors, as described above. It is to be appreciated, inone example, that the one or more processors 1253 and/or memory 1255 maybe configured as described in examples above with respect to the one ormore processors 1203 and/or memory 1205 of UE 1202.

In an example, the one or more processors 1253 and/or memory 1255 mayexecute actions or operations defined by scheduling component 602 or itssubcomponents. For instance, the one or more processors 1253 and/ormemory 1255 may execute actions or operations defined by a resourcegrant generating component 1220 for generating one or more resourcegrants according to a ULL frame structure for one or more UEs. In anaspect, for example, resource grant generating component 1220 mayinclude hardware (e.g., one or more processor modules of the one or moreprocessors 1253) and/or computer-readable code or instructions stored inmemory 1255 and executable by at least one of the one or more processors1253 to perform the specially configured resource grant generatingoperations described herein. Further, for instance, the one or moreprocessors 1253 and/or memory 1255 may execute actions or operationsdefined by an optional channel/interference estimating component 1222for estimating a channel or interference in communications received overthe resource grants from the one or more UEs. In an aspect, for example,channel/interference estimating component 1222 may include hardware(e.g., one or more processor modules of the one or more processors 1253)and/or computer-readable code or instructions stored in memory 1255 andexecutable by at least one of the one or more processors 1253 to performthe specially configured channel and/or interference estimatingoperations described herein. Further, for instance, the one or moreprocessors 1253 and/or memory 1255 may optionally execute actions oroperations defined by an optional RS triggering component 1224 fortriggering RS transmission by one or more UEs. In an aspect, forexample, RS triggering component 1224 may include hardware (e.g., one ormore processor modules of the one or more processors 1253) and/orcomputer-readable code or instructions stored in memory 1255 andexecutable by at least one of the one or more processors 1253 to performthe specially configured SDI request receiving operations describedherein.

It is to be appreciated that transceivers 1206, 1256 may be configuredto transmit and receive wireless signals through one or more antennas,an RF front end, one or more transmitters, and one or more receivers. Inan aspect, transceivers 404, 454 may be tuned to operate at specifiedfrequencies such that UE 1202 and/or eNB 1204 can communicate at acertain frequency. In an aspect, the one or more processors 1203 mayconfigure transceiver 1206 and/or one or more processors 1253 mayconfigure transceiver 1256 to operate at a specified frequency and powerlevel based on a configuration, a communication protocol, etc. tocommunicate uplink signals 1208 and/or downlink signals 1209,respectively, over related uplink or downlink communication channels.

In an aspect, transceivers 1206, 1256 can operate in multiple bands(e.g., using a multiband-multimode modem, not shown) such to processdigital data sent and received using transceivers 1206, 1256. In anaspect, transceivers 1206, 1256 can be multiband and be configured tosupport multiple frequency bands for a specific communications protocol.In an aspect, transceivers 1206, 1256 can be configured to supportmultiple operating networks and communications protocols. Thus, forexample, transceivers 1206, 1256 may enable transmission and/orreception of signals based on a specified modem configuration.

In one example of scheduling ULL resources, FIG. 13 illustrates a method1300 for transmitting communications (e.g., by a UE 1202) according to areceived ULL resource grant. At Block 1302, a UE may receive an uplinkresource grant from a network entity for communicating in a wirelessnetwork. Resource grant receiving component 1210 (FIG. 12) can receivethe uplink resource grant (e.g., uplink resource grant 1280) from thenetwork entity (e.g., eNB 1204) for communicating in the wirelessnetwork. As described, for example, eNB can transmit the uplink resourcegrant as a downlink signal 1209 to UE 1202 via transceiver 1256, whichcan be received by transceiver 1206 and provided to one or moreprocessors 1203 for processing. For example, the resource grant cancorrespond to a ULL resource grant, which can be defined according to aULL frame structure(s) corresponding to a TTI that has a duration thatis less than a duration of a legacy wireless communication technology(e.g., a symbol duration, two or more symbols duration, slot duration,etc. of an LTE subframe). In one example, the ULL resource grant can bedefined according to the ULL frame structure(s) 800 (FIG. 8) and/or 900(FIG. 9), described above, and can thus include a number of RBs and/orRB groups within the TTI. Additionally, in this regard for example,resource grant generating component 1220 (FIG. 12) may generate theresource grant for the UE 1202 according to the ULL frame structure(e.g., to specify resources in the grant based on the ULL framestructure where the UE 1202 and eNB 1204 may operate based on the ULLframe structure), and scheduling component 602 can communicate (e.g.,transmit) the resource grant to UE 1202 via transceiver 1256 for receiptby resource grant receiving component 1210 via transceiver 1206.

In an example, receiving the uplink resource grant at Block 1302 mayoptionally, at Block 1304, receive a multiple-stage resource grant froma network entity. Resource grant receiving component 1210 can receivethe multiple-stage resource grant from the network entity (e.g., eNB1204, core network 130, etc), which may include receiving themultiple-stage resource grant in multiple separate downlink signals 1209transmitted by transceiver 1256 for receipt by transceiver 1206 andprocessing by one or more processors 1203 of UE 1202. For example, theresource grant generated by resource grant generating component 1220 mayinclude a multiple-stage resource grant such that scheduling component602 transmits grant information in multiple instances of communicationsto the UE 1202. For example, in a first stage resource grant, resourcegrant generating component 1220 can include one or more parameters,which may include a modulation and coding scheme (MCS) for uplinkgrants, a transmit power control (TPC) for uplink communications fromthe UE 1202, and/or precoding information. Scheduling component 602 cantransmit the first stage resource grant to UE 1202, which resource grantreceiving component 1210 can receive (e.g., via communicating component661). In one specific example, the first stage resource grant may be10-13 bits in length and may be transmitted via PDCCH, enhanced PDCCH(EPDCCH), etc. from eNB 1204 to UE 1202. For example, in the first stagegrant, the MCS for uplink resource grants can be 5 bits, the TPC can be2 bits, and precoding information can be 3-6 bits.

In, a second stage resource grant, resource grant generating component1220 may include one or more additional parameters, which may include anew data indicator (NDI) to indicate whether the UE 1202 is toretransmit a previous communication or a new communication, a HARQprocess identity to indicate a HARQ process to which the NDI relates, adelta MCS to indicate a change in the MCS from the MCS signaled in thefirst stage resource grant, an RS cyclic shift indicating a cyclic shiftto apply to resource blocks over granted resources when transmitting anRS, a ULL RS triggering indicator (e.g., one or more conditions orrelated parameters for triggering RS transmission as prepared by RStriggering component 1224, which is described further herein), anaperiodic channel state information (CSI) trigger indicating one or moreconditions or related parameters for reporting CSI, and/or an indicationof the granted resources. Resource grant receiving component 1210 canaccordingly receive the multiple stages of the assignment viacommunicating component 661, and can configure communicating component661 to transmit communications to the eNB 1204 using parametersspecified in the multiple stages of the assignment (e.g., using the MCS,applying the TPC, including a RS according to the RS cyclic shift,communicating CSI upon detecting the trigger, etc.). In a specificexample, the second stage resource grant can be 10 bits including a bitdifferentiating whether the grant is for downlink or uplink that is 1bit, the NDI as 1 bit, the delta MCS as 1 bit, the RS cyclic shift(which may be a demodulation RS (DM-RS) cyclic shift) of 1 bit (e.g., toindicate whether to implement cyclic shifting of the DM-RS betweensymbols 0 and 6 for rank 1 communications, or between symbols 0/6 and3/9 for rank 2 communications), the uRS triggering indication of 1 bit,the aperiodic CS trigger of 1 bit, and/or the resource allocation of 4bits.

In addition, in one example, receiving the uplink resource grant atBlock 1302 may optionally, at Block 1306, receive a TBS scalingindication from a network entity. Resource grant receiving component1210 may receive the TBS scaling indication from the network entity(e.g., from eNB 1204). Thus, for example, the resource grant generatedby resource grant generating component 1220 may include an indication ofTBS scaling based on an RB size allocated to the UE 1202 in the resourcegrant. Accordingly, resource grant receiving component 1210 can receivethe TBS scaling indication, and TBS determining component 1214 candetermine a TBS size for communicating using the ULL resource based atleast in part on the TBS scaling indication and/or on bandwidthallocated in the resource grant. Alternatively or additionally, TBSdetermining component 1214 may determine a TBS scaling factor based onone or more other parameters (e.g., a measured throughput incommunicating with the eNB 1204, availability of resources for theuPUSCH transmission, etc.) For example, TBS determining component 1214may select a larger scaling factor where additional resources areavailable for the uPUSCH transmission (e.g., where the additionalresources achieve one or more threshold numbers of resources).Similarly, a smaller scaling factor may be chosen if fewer resources areavailable for the uPUSCH transmission (e.g., where the fewer resourcesare less than one or more threshold numbers of resources). It is to beappreciated that receiving the uplink resource grant at Block 1302 mayalso include receiving other parameters associated with the resourcegrant, such as a starting offset, allocated bandwidth, etc., from whichthe size of one or more RB groups in the uplink resource grant can bedetermined.

At Block 1308, the UE may determine a TTI for an uplink transmissionwithin a subframe based on the uplink resource grant. In an aspect, theTTI includes at least a symbol, one or more symbols, a slot, etc. Inanother aspect, the TTI includes one or more symbols which are a subsetof a plurality of symbols in the subframe. TTI determining component1212 can determine the TTI for the uplink transmission within thesubframe based on the uplink resource grant received by resource grantreceiving component 1210. As described above, with respect to ULL framestructures 800, 900, for example, the TTI can be a symbol duration,multiple symbols duration, slot duration, etc., where an LTE subframecomprises 12 or 14 symbols depending on CP. TTI determining component1212 can determine the TTI for the uplink transmission based at least inpart on a configuration received from the eNB 1204, information in theresource grant received from the eNB 1204 (e.g., an indication ofgranted resources in a second stage resource grant), and/or the like.

At Block 1310, the UE may transmit communications to the network entityover the resources specified in the uplink resource grant during theTTI. For example, in an aspect, communicating component 661 can transmitcommunications (e.g., ULL communications 1282) to the network entity(e.g., eNB 1204) over the resources specified in the uplink resourcegrant during the TTI, where the TTI can be less than a subframe induration, as described. Transmitting the communications, as described,may include the one or more processors 1203 providing data and/orrelated signal information to transceiver 1206 for generating signals totransmit over one or more antennas via an RF front end, etc. Due to theshortened TTI, for example, interference may vary across TTIs (e.g.,across symbols), and thus it may be desirable to perform interferencecancellation at the TTI level for ULL communications (e.g., at thesymbol level, two-symbol level, slot level, etc.). In this regard, inone example, transmitting communications, at Block 1310, may optionally,at Block 1312, puncture one or more symbols with one or more configuredsymbols to facilitate interference cancellation. For example, puncturingmay refer to replacing the one or more symbols with the one or moreconfigured symbols once the symbols are generated from data to betransmitted. Communicating component 661 can puncture the one or moresymbols with the one or more configured symbols, thereby defining one ormore punctured symbols, to facilitate interference cancellation intransmitting the communications to the network entity (e.g., to eNB1204). The one or more symbols to be punctured can be in knownlocations, for example, such that the eNB 1204 can observe the one ormore configured symbols as punctured in the known locations (e.g., wherethe known locations can be configured at the UE 1202 and/or eNB 1204).

For example, the punctured symbols can include one or morecoded/modulated symbols that are punctured (e.g., replaced) beforecommunicating component 661 (e.g., in a processor corresponding totransceiver 1206) performs a DFT to the symbols to generate a signal fortransmission. In addition, for example, the configured symbols can besymbols having a value that is known by the UE 1202 and eNB 1204 (e.g.,stored in a configuration at the UE 1202 (and/or eNB 1204), receivedfrom the eNB 1204, and/or the like). Thus, then known configuredsymbols, can accordingly allow the eNB to identify the configuredsymbols in a transmission from the UE 1202, and can utilize the knownvalue of the configured symbols along with the received transmission toestimate interference over the symbol, subsequent symbols, one or moresymbols of the subframe, etc. Puncturing the symbols with known,configured symbols in this regard may preserve the SC-FDM property ofthe signal to be transmitted from the UE 1202 to eNB 1204. In addition,the punctured symbols may have a modulation order lower than amodulation order corresponding to the uplink resource grant.

Furthermore, as UE 1202 may be operable to communicate using ULL andother RATs (e.g., a legacy wireless communication technology, such asLTE), optionally at Block 1314, the UE may transmit the communicationsbased on other communications related to a second TTI of a subframeduration. In an aspect, the other communications may also be scheduledover the TTI. For example, in an aspect, communicating component 661 cantransmit the communications (e.g., ULL communications 1282) based on theother communications (e.g., LTE communications 1282) related to thesecond TTI of the subframe duration, where the other communications arealso scheduled over the TTI (e.g., ULL TTI). As described, transmittingthe communications, as described, may include the one or more processors1203 providing data and/or related signal information to transceiver1206 for generating signals to transmit over one or more antennas via anRF front end, etc. In other words, the “communications” may be any ULLcommunications, while the “other communications” may be anycommunications related to a TTI different from the ULL TTI, such as butnot limited to TTIs defined in legacy LTE communications, TTIsassociated with other communication in other RATs, etc. Accordingly, inan aspect, communicating component 661 may handle potential conflictsbetween scheduled concurrent transmission of the communications (e.g.,over ULL) and the other communications (e.g., over a legacy wirelesscommunication technology such as LTE) in the same time interval (e.g.,subframe or portion thereof).

For example, transmitting the communications based on othercommunications at Block 1314 may optionally include, at Block 1316,transmitting the communications and the other communicationsconcurrently during the TTI. For example, in an aspect, communicatingcomponent 661 may transmit both the communications and othercommunications concurrently during the TTI. This may include the one ormore processors 1203 generating signals for providing to transceiver1206 for transmission where the signals may include the communicationsand other communications in similar frequency and/or time resourcescorresponding to the signals. For example, this can includecommunicating component 661 transmitting the communications and othercommunications over respective resources where RBs and/or RB groupsassigned to the communications and other communications do not conflict(though the communications and other communications may overlap in thetime domain in one or more subframes or portions thereof). In anotherexample, communicating component 661 may concurrently transmit thecommunications and the other communications where the othercommunications include control information by including (e.g.,piggybacking) the control information from the other communications onthe ULL communications (e.g., piggyback control information from PUCCHor PUSCH onto uPUSCH transmission, etc.).

For example, referring to FIGS. 8 and 9, this piggybacking may includecommunicating component 661 transmitting the control information for theother communications in PUCCH region 802 (and/or PUSCH region 806depending on the frame structure configured to ULL communications) whilecommunicating the ULL communications in a ULL region (e.g., uPUSCHregion 810 and/or uPUCCH region 808). The PUCCH communications mayinclude uplink control indicators (UCI) such as ACK/NACK, schedulingrequest (SR), CSI, etc. In another example, however, communicatingcomponent 661 may transmit the control information for the othercommunications in region 804.

In another example, transmitting the communications at Block 1314 mayoptionally, at Block 1318, prioritize the communications over the othercommunications. Communication prioritizing component 1216 may prioritizethe communications (e.g., the ULL communications) over the othercommunications (e.g., LTE communications) in the TTI. For example, oneor more uplink resource grants received from the eNB 1204 may result incommunications (e.g., ULL communications) and other communications(e.g., LTE communications) being scheduled in similar resources (e.g.,where the TTIs overlap), which is referred to herein as a collision orcolliding resources. For example, ULL communications may be scheduled ina symbol TTI where the symbol is within a subframe TTI over which othercommunications are scheduled. In this regard, prioritizingcommunications at Block 1318 may include communication prioritizingcomponent 1216 prioritizing the ULL communications for transmission inresources that overlap transmission of the other communications,communication prioritizing component 1216 dropping the othercommunications over the entire TTI (e.g., the LTE subframe) inprioritizing the ULL communications that may occur in subsequent TTIs inthe subframe, etc. This can preserve a single-carrier waveform insignals generated for transmitting the ULL communications, which may bebeneficial at least where UE 1202 is link-limited, as the single-carriersignal exhibits low PAPR. In the above examples related to prioritizingthe communications over other communications, the communications mayrelate to uPUCCH communications, uPUSCH communications, uRScommunications, etc. in ULL, and/or the other communications may relateto PUCCH communications, PUSCH communications, SRS communications, etc.in LTE.

Where ULL communications are prioritized over PUCCH LTE communications,however, for example, dropping one or more PUCCH symbols may causenon-orthogonality with other PUCCHs of the same RB based on currentlydefined PUCCH formats in LTE (e.g., formats 1, 1a, 1b, 2a, 2b, 3, etc.)due to time-domain spreading over the RB. Accordingly, for example,prioritizing the ULL communications may include communicating component661 transmitting the other communications (e.g., PUCCH communications inLTE) using newly defined formats outside of the PUCCH formats currentlydefined in LTE, where the newly defined formats are not time-domainspread over an RB or otherwise allow for gaps in the time-domainspreading. In another example, communicating component 661 may transmitthe other communications in different RBs than those used to transmitthe ULL communications based on determining to transmit the ULLcommunications in RBs that overlap the other communications, etc.

In addition or in the alternative, for example, transmitting thecommunications based on other communications at 1314 may optionally, atBlock 1320, prioritize the other communications over the communications.Communication prioritizing component 1216 can prioritize the othercommunications (e.g., LTE communications) over the communications (e.g.,ULL communications) in some examples. For example, where the othercommunications correspond to higher layer signaling (e.g., RRCsignaling, such as signaling related to the RRC connection with eNB1204), communication prioritizing component 1216 can prioritize theother communications, such that the ULL communications are nottransmitted in the subframe or portion thereof over which thecommunications and other communications are both initially scheduled(e.g., collide).

In another example, in transmitting communications at Block 1310, it ispossible that resources for uPUSCH and uRS communications in ULL collide(e.g., where resource grant receiving component 1210 receives a resourcegrant with a uRS trigger). In one example, when such a collision exists,communicating component 661 can transmit the uPUSCH instead of the uRSduring the TTI. In another example, communicating component 661 maytransmit both uPUSCH and uRS concurrently during the TTI. In this case,communicating component 661 can transmit these two channels such thatthe channels may share a same bandwidth by occupying different resourcesin the same bandwidth during the TTI.

In another example, it is possible that resources for uPUCCH and uRScommunications in ULL collide during the TTI. In one example, when sucha collision exists, communicating component 661 can transmit the uPUCCHinstead of the uRS during the TTI. In another example, communicatingcomponent 661 may transmit both uPUCCH and uRS concurrently during theTTI. In this case, communicating component 661 can transmit these twochannels such that the channels may share a same bandwidth by occupyingdifferent resources in the same bandwidth during the TTI.

In another example, communicating component 661 may multiplex one ormore symbols with a set of modulation symbols to facilitate channelestimation or interference estimation over the TTI, as described above.In one example, the set of modulation symbols may have predeterminedvalues (including zero), which can be known to eNB 1204 or other networkentities. In another example, the set of modulation symbols may have amodulation order lower than a modulation order corresponding to theresource grant to facilitate identifying the modulation symbols based onthe lower modulation order over the remaining symbols corresponding tothe resource grant.

FIG. 14 illustrates an example method 1400 for scheduling uplinkcommunications (e.g., by an eNB 1204) for one or more UEs based on a TTIhaving a duration that is less than that of an underlying legacycommunication technology (e.g., less than a subframe in LTE). At Block1402, an eNB may generate an uplink resource grant for a UE to scheduleuplink communications for the UE based on a TTI comprising one or moresymbols, a slot, etc. which are a subset of a plurality of symbols in asubframe. For example, in an aspect, resource grant generating component1220 can generate the uplink resource grant for the UE 1202 to scheduleuplink communications for the UE 1202 based on the TTI comprising one ormore symbols, which are a subset of the plurality of symbols in thesubframe, as described. For example, resource grant generating component1220 can generate the uplink resource grant for ULL communications basedon a TTI having a duration of, for instance, one symbol, or two or moresymbols, or one slot, etc. In addition, as described, resource grantgenerating component 1220 can generate the uplink resource grant toinclude one or more RB groups within a TTI allocated for control or datatransmissions on one or more uplink channels. In one example, the ULLresource grant can be defined according to the ULL frame structure(s)800 (FIG. 8) and/or 900 (FIG. 9), described above. Moreover, asdescribed, resource grant generating component 1220 can generate theuplink resource grant to include a plurality of RB groups that aresimilar in size based on an amount of a system bandwidth that isavailable to be granted to the UE 1202 over the TTI.

At Block 1404, the eNB may communicate the uplink resource grant to theUE. For example, in an aspect, scheduling component 602 can communicatethe uplink resource grant (e.g., uplink resource grant 1280) to the UE.Communicating, as described, may include the one or more processors 1253providing data and/or related signal information to transceiver 1256 forgenerating signals to transmit over one or more antennas via an RF frontend, etc. For example, scheduling component 602 may communicate theuplink resource grant over one or more downlink channels in downlinksignals (e.g., a PDCCH, or uPDCCH, etc.), as described, such thatresource grant receiving component 1210 can obtain the uplink resourcegrant (e.g., via transceiver 1206), and can communicate over resourcesindicated in the uplink resource grant (e.g., via transceiver 1206), asdescribed. Thus, at Block 1406, the eNB may receive uplinkcommunications from the UE during the TTI based on the uplink resourcegrant. Scheduling component 602 can receive the uplink communications(e.g., ULL/LTE communications 1282) from the UE 1202 during the TTIbased on the uplink resource grant. Receiving communications, asdescribed, may include the transceiver 1256 receiving one or moresignals (e.g., via an RF front end) and providing information regardingthe signals to the one or more processors 1253 for decoding,demodulation, or otherwise processing the signals to obtain datatherefrom.

In addition, in an example, communicating the uplink resource grant atBlock 1404 may optionally, at Block 1408, communicate a multiple-stagegrant to the UE. For example, in an aspect, resource grant generatingcomponent 1220 can generate the uplink resource grant as amultiple-stage grant, and scheduling component 602 can communicate themultiple-stage grant to the UE 1202. Thus, for example, one or moreprocessors 1253 can generate multiple signals for transmitting themultiple-stage grant, and transceiver 1256 can transmit the multiplesignals via an RF front end and one or more antennas. As described, themultiple-stage grant may include a first stage resource grant, which mayinclude a MCS for uplink grants, a TPC for uplink communications fromthe UE 1202, and/or precoding information, etc., and/or a second stageresource grant, which may include a NDI, a delta MCS, an RS cyclic, anRS triggering, an aperiodic CSI trigger, an indication of the grantedresources, etc.

Moreover, in an example, communicating the uplink resource grant atBlock 1404 may optionally, at Block 1410, communicate one or moreparameters regarding the uplink resource grant to the UE. For example,in an aspect, scheduling component 602 can communicate the one or moreparameters regarding the uplink resource grant to the UE 1202. In oneexample, resource grant generating component 1220 may generate theuplink resource grant to include the one or more parameters. Forexample, resource grant generating component 1220 may specify a startingoffset and/or system bandwidth in the resource grant to indicate a sizeof the one or more RB groups within a TTI allocated for control or datatransmissions on one or more uplink channels. In another example,resource grant generating component 1220 may specify a TBS scalingfactor in the uplink resource grant based on the size of the uplinkresource grant (e.g., based on the size and/or number of the one or moreRB groups). As the bandwidth allocated in the uplink resource grant isconfigurable, the TBS scaling factor can indicate scaling for theallocated bandwidth to achieve a certain TBS.

Optionally, at Block 1412, the eNB may perform at least one of channelestimation or interference estimation based at least in part oncomparing one or more modulation symbols received in the uplinkcommunications with a set of configured modulation symbols. For example,in an aspect, channel/interference estimating component 1222 can performat least one of channel estimation or interference estimation based atleast in part on comparing the one or more modulation symbols receivedin the uplink communications with the set of configured modulationsymbols. As described above, UE 1202 can puncture one or more symbols inthe uplink communications with the one or more configured modulationsymbols, which can be configured at each of UE 1202 and eNB 1204,configured by eNB 1204 to UE 1202, etc., such that UE 1202 and eNB 1204know the symbols, location of the symbols, etc. In this regard, forexample, channel/interference estimating component 1222 can observe thesymbols as received in the known locations for punctured symbols of theuplink communications, and can compare the punctured symbols to theknown one or more configured symbols to determine the channel and/orinterference associated with the uplink communications. In addition, thepunctured symbols may have a modulation order lower than a modulationorder corresponding to communications over the resources of the uplinkresource grant, as described, to facilitate detection and/or morereliable transmission thereof.

Further, optionally, at Block 1414, the eNB may generate a second uplinkresource grant for the UE or one or more other UEs to schedule uplinkcommunications based on a second TTI. For example, in an aspect,resource grant generating component 1220 can generate the second uplinkresource grant for the UE 1202 or one or more other UEs to scheduleuplink communications based on the second TTI. As described, eNB 1204may be capable of communicating using ULL communications and some othercommunications, e.g., an underlying legacy communication technology,such as LTE. Thus, resource grant generating component 1220 may generatethe second uplink resource grant for the UE 1202 or one or more otherUEs based on a TTI that is a subframe in duration, as in LTE. In thisexample, the eNB 1204 may support ULL and LTE communications.

In addition, optionally, at Block 1416, the eNB may communicate thesecond uplink resource grant to the UE or the one or more other UEs,and/or, at Block 1418, the eNB may receive additional uplinkcommunications from the UE or the one or more other UEs during thesecond TTI. For example, in an aspect, scheduling component 602 maycommunicate the second uplink resource grant to the UE 1202 or the oneor more other UEs in one or more downlink signals 1209 transmitted bytransceiver 1206 and/or may receive additional uplink communications inone or more uplink signals 1208 transmitted by the UE 1202, e.g., othercommunications of an underlying legacy communication technology, such asLTE, from the UE 1202 or the one or more other UEs during the secondTTI, which may overlap with the TTI over which the uplink communicationsare received at Block 1406.

FIG. 15 illustrates an example method 1500 for determining to transmit(e.g., by a UE 1202) a RS based on a received trigger. At Block 1502,the UE may receive, from a network entity, an uplink resource grantincluding an indicator of whether to transmit a DM-RS for an uplinkcontrol or data channel. For example, in an aspect, resource grantreceiving component 1210 can receive, from the network entity (e.g., eNB1204), the uplink resource grant (e.g., uplink resource grant 1280)including the indicator of whether to transmit the DM-RS for an uplinkcontrol or data channel. As described, for example, receiving the uplinkresource grant and indicator may include receiving the uplink resourcegrant and indicator in one or more downlink signals 1209 via atransceiver 1206, and processing the signal(s) 1209 by one or moreprocessors 1203 to obtain information specific to the uplink resourcegrant and/or indicator. For example, the DM-RS can correspond to the uRSdescribed above for ULL communications. In this regard, resource grantgenerating component 1220 may generate the resource grant for UE 1202that may include the indicator of whether to transmit the DM-RS, whichis generated by RS triggering component 1224, and scheduling component602 can transmit the resource grant to UE 1202 for receipt by resourcegrant receiving component 1210 via communicating component 661.

At Block 1504, the UE may determine whether to transmit the DM-RS in atleast one TTI based at least in part on the indicator. RS triggerreceiving component 1218 can determine whether to transmit the DM-RS inat least one TTI based at least in part on the indicator. For example,if the indicator is received, RS trigger receiving component 1218 candetermine to transmit the DM-RS (e.g., the uRS) in at least one TTI.Furthermore, RS trigger receiving component 1218 may determine the TTIwithin which to transmit the DM-RS based on the RS trigger, which may bereceived in a multiple-stage grant, as described above. For example, theresource grant may include an explicit indication of a TTI (e.g., a TTIindex within a subframe or other identifier), an implicit indication ofa TTI (e.g., an indication of number of TTIs following the TTI overwhich the resource grant is received), etc., to use for transmitting theDM-RS.

Optionally, at Block 1506, the UE may receive one or more parametersrelated to transmitting the DM-RS in one or more TTIs. For example, inan aspect, RS trigger receiving component 1218 may receive the one ormore parameters related to transmitting the DM-RS in the one or moreTTIs. For example, RS triggering component 1224 can signal, e.g.,transmit in one or more downlink signals 1209 via transceiver 1256, theone or more parameters to the UE 1202, such as in an RRC or otherconfiguration. In another example, RS triggering component 1224 cansignal the one or more parameters to the UE 1202 in the multiple-stageresource grant, and/or the like. In any case, RS trigger receivingcomponent 1218 can determine the one or more parameters based onreceiving the configuration, in one example. The one or more parametersfor transmitting the DM-RS may include one or more periodicityparameters for periodic transmission of the DM-RS, a bandwidth fortransmitting the DM-RS, one or more frequency locations over which totransmit the DM-RS in configured TTIs (e.g., symbols), a hopping patternto use in transmitting the DM-RS in different frequency locations over anumber of configured TTIs, a number of antenna ports to use intransmitting the DM-RS, a comb level (e.g., as defined for legacy SRSsymbol) to use in transmitting the DM-RS, etc. In another example, RStrigger receiving component 1218 can determine the one or moreparameters based on similar parameters received for uPUCCH and/or uPUSCHtransmissions.

For periodic uRS transmissions, for example, at least a subset of theone or more parameters can be related to a periodic RS trigger, such asa periodicity (e.g., an indication of units of TTIs, milliseconds (ms),or other parameter indicating TTIs over which uRS is to be periodicallytransmitted). The one or more parameters may also define a periodicitysuch that uRS is transmitted in a certain set of TTIs in a subframe(e.g., every N subframes, where N can be a positive integer). In anotherexample, the one or more parameters may include an indication ofbandwidth over which the uRS is to be transmitted (e.g., a number ofresource blocks). In one example, the indication of bandwidth mayinclude an integer multiple of 4 resource blocks. In another example,the one or more parameters may relate to defining hopping pattern forthe uRS, where resources utilized to transmit the uRS can hop from onefrequency location in one TTI to another frequency location in anotherTTI (e.g., based on the parameter or otherwise). Thus, for example, theone or more parameters may include an indication of the frequencylocations that define the pattern, or an indication of spacing betweenfrequency resources between one or more TTIs, etc. Moreover, forexample, the one or more parameters may include an indication of anumber of antenna ports to utilize in transmitting the uRS. For example,where the uRS relates to uPUCCH transmissions (and is transmitted in theuPUCCH region 808 as shown in FIG. 11, for example), the number ofantenna ports can be fixed at one. Where the uRS relates to uPUSCHtransmission (and is transmitted in the uPUSCH region 810 as shown inFIG. 11), the number of antenna ports can be one, two, four, etc., inconnection with possible UL MIMO operations on uPUSCH. Moreover, eachantenna port may be non-precoded and/or may be similar to a 1-port SRS.Additionally, the one or more parameters may assign different cyclicshifts or comb offsets for each antenna port. For example, periodic uRScan be used for uPUCCH and/or uPUSCH demodulation when aperiodic uRS isnot available, or in combination with aperiodic uRS when it isavailable. Periodic uRS may also be used to assist in uplink subbandbased scheduling especially when uRS is enabled with frequency hoppingin different transmissions. Periodic uRS can also provide a “keep-alive”UL operation in terms of uplink power control, uplink time/frequencytracking, etc.

For aperiodic uRS, an aperiodic RS trigger can be defined as relating toeither a TTI based on a timing relationship (e.g., 3 TTIs after thetrigger), and/or additionally based on a periodicity. (e.g., anindication of units of TTIs, milliseconds (ms), or other parameterindicating TTIs over which uRS is to be periodically transmitted). Theone or more parameters may also define a periodicity such that uRS ispossibly transmitted in a certain set of symbols in a subframe (e.g.,every N subframes, where N can be a positive integer). As an example, ifthe one or more parameters relate to transmitting aperiodic uRStriggered in symbol n, where n can be a positive integer, if symbol n+3is not configured as a symbol for aperiodic uRS transmission but symboln+4 is configured as a symbol for aperiodic uRS transmission,communicating component 661 can transmit the aperiodic uRS in symbol n+4instead. As described with respect to periodic uRS, the one or moreparameters may include a bandwidth over which the uRS is to betransmitted. Aperiodic uRS, once triggered, may be transmitted just once(one-shot transmission) or multiple times (multi-shot transmission). Incase of multi-shot aperiodic uRS, hopping can be enabled (e.g., andassociated hopping pattern parameter(s) configured), such that uRS canhop from one frequency location in one transmission to another frequencylocation in another transmission. Aperiodic uRS may also be configuredwith a number of antenna ports, as similarly described with respect theperiodic uRS (e.g., such that aperiodic uRS for uPUCCH can use oneantenna port and/or uRS for uPUSCH can use 1, 2, 4, etc. antenna ports).As described above, in this example, each antenna port may benon-precoded and/or may be similar to a 1-port SRS. Additionally, theone or more parameters may assign different cyclic shifts or comboffsets for each antenna port. Aperiodic uRS can be used for uPUCCHand/or uPUSCH demodulation by itself, or in combination with periodicuRS when it is available. When there is an accompanying uPUCCH oruPUSCH, uRS parameters can be consistent or be based on uPUCCH or uPUSCHparameters. For example, uRS may have the same bandwidth, frequencylocation, and the number of antenna ports as the corresponding uPUSCH.When there is no accompanying uPUCCH or uPUSCH, uRS parameters can bebased on some dynamic indication in an uplink resource grant, forexample.

In either case, optionally, at Block 1508, the UE may transmit the DM-RSin the TTI based on determining to transmit the DM-RS. For example, inan aspect, communicating component 661 may transmit the DM-RS (e.g., asULL/LTE communication 1282) in the TTI based on RS trigger receivingcomponent 1218 determining to transmit the DM-RS in the TTI. Thus,transmitting the DM-RS in the TTI may optionally include, at Block 1510,transmitting the DM-RS based on one or more configured parameters. Theone or more configured parameters can correspond to the one or moreparameters received or determined by RS trigger receiving component1218, as described above, for transmitting a periodic and/or aperiodicDM-RS (e.g., uRS) in one or more TTIs. Transmitting the RS, asdescribed, may include communicating component 661 transmitting theDM-RS in the one or more TTIs where one or more processors 1203 cangenerate the corresponding signal for transmission by transceiver 1206over one or more antennas via an RF front end (e.g., using the specifiedfrequency location, which may be based on a hopping pattern, using thespecified number of antenna ports or comb level, and/or the like). Inone example, as shown in timelines 1000, 1010 above, the DM-RS (e.g.,uRS) transmitted by communicating component 661 may occupy one symbol.In addition, for example, each DM-RS may have configurable bandwidth, aconfigurable hopping pattern, such that the DM-RS can hop acrosssubbands, different comb offsets, etc. (e.g., which can be determined byeNB 1204 and controlled via RS triggering component 1224 specifying oneor more parameters to the UE 1202). Moreover, each DM-RS may have one ormore ports that are non-precoded and/or can be indicated via cyclicshifts representative of the one or more ports. The cyclic shifting canbe configured by RS triggering component 1224 and specified to UE 1202(e.g., as part of the resource grant or otherwise).

In an example, communicating component 661 can transmit an aperiodic uRSthat is triggered by receiving the uplink resource grant (e.g., in adownlink control indicator (DCI)) based on the one or more parametersreceived from the eNB 1204. For example, communicating component 661 cantransmit the uRS such that the timing is different from thecorresponding uPUSCH (e.g., transmit the uRS 3 TTIs after the uplinkgrant is received where the uPUSCH is transmitted 4 TTIs after theuplink grant, as shown in timeline 1010 of FIG. 10). In another example,communicating component 661 can transmit a periodic uRS that istriggered based on the one or more parameters that may identify explicitTTIs for transmitting the uRS (e.g., after 6 TTIs then 9 TTIs, as shownin timeline 1000 of FIG. 10). In addition, in an example, communicatingcomponent 661 may transmit a uRS for each of control and datacommunications in frequency locations associated with control and datacommunications, respectively, as shown in FIG. 11 (e.g., uPUCCH uRS inuPUCCH region 808, and uPUSCH uRS in uPUSCH region 810).

Optionally, at Block 1512, the UE may transmit at least one of a controlchannel or data channel in a same or different TTI as the DM-RS based atleast in part on the resource grant. For example, in an aspect,communicating component 661 can transmit at least one of a controlchannel or data channel in the same or different TTI as the DM-RS basedat least in part on the resource grant (e.g., received from eNB 1204).As similarly described above in FIG. 13, the control or data channel maycorrespond to PUCCH, PUSCH, SRS, etc. in LTE, and transmission of theDM-RS may be prioritized where parallel transmission is not allowed;thus, in this example, transmitting at least one control channel or datachannel at Block 1512 can include transmitting the at least one controlchannel or data channel in a different TTI as the DM-RS. In anotherexample, the control or data channel may correspond to uPUCCH or uPUSCH,and the uRS may be transmitted in conjunction therewith or not; thus, inthis example, transmitting at least one control channel or data channelat Block 1512 can include transmitting the at least one control channelor data channel in the same or different TTI as the uRS, etc., asdescribed above.

For example, where the uRS collides with PUSCH transmission in LTE, theuRS can be prioritized over the PUSCH transmission by the UE 1202 suchthat in colliding symbols where the uRS and PUSCH are transmitted,communicating component 661 can drop PUSCH transmission in the collidingsymbols, and/or may drop the entire TTI for PUSCH. Similarly,communicating component 661 may drop SRS transmission in symbols thatcollide with uRS transmission. In addition, as described above withrespect to collision between ULL communications and PUCCH in LTE, uRSmay generally be prioritized over PUCCH such that communicatingcomponent 661 can drop PUCCH transmission in the colliding symbols,and/or may drop the entire TTI for PUCCH, but in some cases mayprioritize PUCCH such that uRS transmissions in colliding symbols aredropped (e.g., where the PUCCH communications correspond to RRC layercommunications). Additionally, as described above with respect tocolliding ULL and PUCCH communications, additional PUCCH formats may bedefined to allow communicating component 661 to place the PUCCHs indifferent RBs where dropping one or more symbols of the PUCCH may causenon-orthogonality with other PUCCHs based on the currently defined PUCCHformats.

FIG. 16 illustrates an example method 1600 for communicating anindicator (e.g., by an eNB 1204) of whether to transmit a DM-RS to a UE(e.g., UE 1202). At Block 1602, the eNB may generate an uplink resourcegrant including an indicator of whether to transmit a DM-RS for anuplink control or data channel in at least one TTI. Resource grantgenerating component 1220 can generate the uplink resource grantincluding the indicator of whether to transmit the DM-RS for the uplinkcontrol or data channel in at least one TTI. For example, RS triggeringcomponent 1224 may indicate a trigger for transmitting the DM-RS (e.g.,uRS) to the resource grant generating component 1220 to facilitategenerating the resource grant with the trigger for transmitting DM-RS.Generating the uplink resource grant including the indicator at Block1602 may include, at Block 1604, one or more parameters in the uplinkresource grant related to the DM-RS transmission. Resource grantgenerating component 1220 can include the one or more parameters in theuplink resource grant where the parameter(s) are related to the DM-RStransmission. As described, the one or more parameters may be related totransmitting a periodic or aperiodic DM-RS and may include one or moreof an explicit or implicit indication of a TTI during which to transmitthe DM-RS, a cyclic shift, a bandwidth, a hopping pattern, one or morefrequency locations, one or more antenna ports, one or more comb levels,etc. for the UE 1202 to utilize in transmitting the DM-RS.

At Block 1606, the eNB may transmit the uplink resource grant andindicator to a UE. Scheduling component 602 can transmit the uplinkresource grant (e.g., uplink resource grant 1280) and indicator to theUE. For example, scheduling component 602 can communicate the uplinkresource grant to the UE 1202 in RRC signaling, in a multiple-stagegrant (e.g., as the RS trigger in the second stage, as described above),and/or the like. As described, scheduling component 602 can transmit theuplink resource grant and indicator based on providing data related tothe grant and indicator to one or more processors 1253 for generatingsignal information and providing the signal information to transceiver1256 generating and transmitting one or more signals indicating thegrant and/or indicator via one or more antennas via an RF front end.Resource grant receiving component 1210 and/or RS trigger receivingcomponent 1218 can receive the uplink resource grant and/or theindicator, as described. The uplink resource grant may correspond togranting resources based on a ULL TTI for transmitting uplink controland/or data and for transmitting uRS, as described.

Optionally, at Block 1608, the eNB may receive one or more DM-RSs fromthe UE in the at least one TTI. Scheduling component 602 can receive theone or more DM-RSs from the UE 1202 in the at least one TTI. In anexample, scheduling component 602 can accordingly use the DM-RS indemodulating communications received over the corresponding resources ofthe uplink resource grant. Receiving the one or more DM-RSs at Block1608 may include, at Block 1610, receiving the one or more DM-RSs (e.g.,as ULL/LTE communication 1282) based at least in part on the one or moreparameters. Thus, as described, the parameters may explicitly orimplicitly indicate the at least one TTI over which the DM-RS is to betransmitted by the UE 1202, and scheduling component 602 may receive theDM-RS in the at least one TTI. Similarly, scheduling component 602 mayreceive the DM-RS over the bandwidth, according to the hopping patternor frequency locations, via the number antenna ports, according to thecomb level, etc. specified in the one or more parameters. In oneexample, scheduling component 602 may receive separate uRSs for controland data communications, where the uRSs may each be received infrequency resources related to the control and data communications,respectively, as shown in FIG. 11.

FIG. 17 illustrates an example method 1700 for transmitting uplinkcontrol data (e.g., by a UE 1202) in ULL. At Block 1702, a UE maydetermine a TTI for an uplink control channel transmission within asubframe. In an aspect, the TTI includes a symbol, a number of symbols,a slot, etc. which are a subset of a plurality of symbols in thesubframe. TTI determining component 1212 can determine the TTI for anuplink control channel transmission within the subframe. This can bebased on a resource grant received by resource grant receiving component1210 from eNB 1204 (e.g., uplink resource grant 1280), which mayindicate the TTI duration, the type of communication technology (e.g.,ULL), etc. as described, in one example. Moreover, for example, the TTIcan be of a symbol duration, multiple symbols duration, slot duration,etc., as described.

Optionally, at Block 1704, the UE may determine a resource location fortransmitting control data based on a RB group index associated adownlink control or data channel. Communicating component 661 maydetermine the resource location for transmitting control data based onthe RB group index associated with the downlink control or data channel.For example, communicating component 661 may receive downlink controland/or data channel communications from eNB 1204, as described, and maydetermine the resource location for transmitting control data for thedownlink control and/or data channel based on the receivedcommunications. For example, communicating component 661 may determinethe resource location to be the same as the RB group index over whichthe downlink control and/or data channel is/are received but in asubsequent TTI, a resource location that is an offset from the RB groupindex (e.g., where the offset can be received in the resource grant byresource grant receiving component 1210), etc.

Optionally, at Block 1706, the UE may determine a number of RBs for theuplink control channel. Communicating component 661 can determine thenumber of RBs for the uplink control channel. For example, communicatingcomponent 661 can determine the number of RBs for the uplink controlchannel based at least in part on the uplink resource grant receivedfrom the eNB 1204 (e.g., based on an indication of resource s allocatedby the resource grant). In another example, communicating component 661can determine the number of RBs for the uplink control channel based atleast in part on determining a payload size of the control data to betransmitted (e.g., determining a size in bytes of the payload, an MCSand/or an achievable throughput that may be related to the MCS, etc.).

At Block 1708, the UE may transmit uplink control data over the uplinkcontrol channel during the TTI. Communicating component 661 can transmitthe uplink control data (e.g., as ULL/LTE communication 1282) over theuplink control channel during the TTI. As described, the uplink controlchannel may be transmitted according to a received resource grant thatindicates uplink control channel resources over the TTI including one ormore RB or RB groups within the TTI. Communicating component 661 canschedule and transmit the control data additionally based on determinedresource locations (e.g., based on RB group index of related downlinkcontrol or data channels), the determined number of RBs, and/or thelike. The control data can include ACK/NACK feedback for data receivedin a downlink channel in a prior TTI, SR, etc., and communicatingcomponent 661 may additional use different signaling for thetransmission. As described, transmitting the uplink control data mayinclude the one or more processors 1203 providing data and/or relatedsignal information to transceiver 1206 for generating signals totransmit over one or more antennas via an RF front end, etc.

For example, where the uplink control data relates to SR to betransmitted in the uplink control channel, resource grant generatingcomponent 1220 may generate an associated resource grant for UE 1202that specifies RRC configured resources (e.g., RBs and/or cyclic shifts)for transmitting SR in ULL. Resource grant receiving component 1210 mayreceive the resource grant, and communicating component 661 canaccordingly transmit SR to eNB 1204 based on the configured resources(e.g., using the RBs and/or corresponding cyclic shifts). In an example,RBs indicated by resource grant generating component 1220 may include anexplicit indication of RBs, a number of RBs which are to start with anRB corresponding to or offset from an RB group index of thecorresponding control or data channel, etc.

In another example, the UE, at Block 1708, may optionally, at Block1710, transmit the control data using one or more different cyclicshifts to indicate one or more values of the control data. Communicatingcomponent 661 can transmit the control data using the one or more cyclicshifts to indicate the one or more values of the control data. Forexample, where only ACK/NACK is to be transmitted in the uplink controlchannel, resource grant generating component 1220 may generate aresource grant for UE 1202 for transmitting over PUCCH. Resource grantreceiving component 1210 may receive the resource grant, andcommunicating component 661 can accordingly transmit ACK/NACK to eNB1204 over PUCCH based at least in part on a block index of thecorresponding uPDCCH data received from eNB 1204. Resource grantgenerating component 1220 may specify different cyclic shifts for ACKand NACK, which communicating component 661 can utilize in transmittingACK and NACK. For example, cyclic shift 0 may be used for ACK whilecyclic shift 6 may be used for NACK. In addition, in an example,resource grant generating component 1220 may specify different cyclicshifts for combined transmission of SR and ACK or NACK (e.g., in theresource grant), which communicating component 661 can utilize intransmitting SR with ACK or NACK. For example, cyclic shift 2 may beused for ACK and a positive SR, while cyclic shift 8 may be used forNACK and a positive SR.

Moreover, at Block 1708, the UE may also optionally, at Block 1712,transmit the control data instead of or along with a RS. Communicatingcomponent 661 can transmit the control data instead of or along with theRS. For example, the resource grant may include a RS trigger (e.g., fordetermining when to transmit a uRS). Where transmission of the uRScollides with transmission of the control data, communicating component661 can determine whether to transmit the control data instead of oralong with the uRS, as described previously. For example, where the uRScollides with transmission of the uplink control channel uPUCCH,communicating component 661 can transmit uPUCCH and drop uRS, transmituRS and drop uPUCCH (e.g., where transmitting the uplink control data atBlock 1708 is optional), or can transmit both. To transmit both, forexample, communicating component 661 may transmit uPUCCH if it is SR orACK/NACK by transmitting uRS with different cyclic shift(s) to indicatethe SR or ACK/NACK. If both SR and ACK/NACK are scheduled along withuRS, SR may be dropped in this instance.

Additionally, in an example, and at Block 1714, the UE may bundleACK/NACK for at least one of a plurality of codewords or a plurality ofcarriers for transmitting over the uplink control channel. Communicatingcomponent 661 can bundle the ACK/NACK for at least one of the pluralityof codewords, which may be over a plurality of carriers (e.g., in MIMOcommunications or carrier aggregation) for transmitting over the uplinkcontrol channel. For example, bundling ACK/NACK can include specifying asingle ACK/NACK value for the plurality of codewords or carriers (e.g.,ACK if all values are ACK, and NACK if at least one value is NACK,etc.). Bundling can also include spatial bundling of the ACK/NACKvalues.

In another example, transmitting the uplink control data at Block 1708may include transmitting the uplink control data as two or more ACK/NACKbits for each of two or more codewords and/or one or more carriers. Inaddition, in an example, spatial bundling within a carrier can beenabled such that N ACK/NACK bits can be generated for N carriers, whereN is an integer. Corresponding, uPUCCH can be designed to accommodatetwo or more ACK/NACKs by utilizing more resource blocks and/or morepossible cyclic shifts within a resource block to indicate multipleACK/NACK values. If two or more resource blocks are used fortransmitting the uplink control data at Block 1708, the cyclic shiftutilized one RB can be the same or different that of another RB.

In one example, transmitting the uplink control data at Block 1708 maynot include transmitting a periodic CSI report. In such a case,communicating component 661 may report the periodic CSI based on the1-ms TTI (e.g., using PUCCH in LTE instead). Thus, for example,transmitting uplink control data at Block 1708 may include transmittingthe uPUCCH though the UE 1202 may additionally be triggered orconfigured to transmit PUCCH either simultaneously or in a differentTTI.

In another example, in addition to 1-symbol uPUCCH, uPUCCH may occupytwo or more symbols. Thus, for example, TTI determining component 1212can determine different TTIs (e.g., symbols) for transmitting thecontrol data. Moreover, communicating component 661 may determinedifferent resource blocks in the different TTIs for transmitting thecontrol data such that frequency diversity gain can be achieved. As oneexample, communicating component 661 can determine the different RBs touse in two TTIs (e.g., 2 symbols) such that a 2-symbol uPUCCHtransmission may be transmitted using mirror hopping in frequency (e.g.,if a RB index n is used in a symbol, a RB index N−n can be used in asecond symbol, where N is a total number of RBs, e.g., equal to uplinkbandwidth in number of RBs). For example, communicating component 661can transmit the 2-symbol uPUCCH in response to a 2-symbol downlinktransmission received by communicating component 661 and/or a downlinktransmission of a different time duration (e.g., 1 symbol).

FIG. 18 illustrates an example method 1800 for transmitting (by an eNB1204) uplink resource grants to a UE for receiving uplink control datain ULL. At Block 1802, the eNB may generate an uplink resource grant fora UE based on determining a TTI within a subframe. In an aspect, the TTIincludes a symbol, a number of symbols, a slot, etc., which are a subsetof a plurality of symbols in the subframe. Resource grant generatingcomponent 1220 can generate the uplink resource grant for the UE (e.g.,UE 1202) based on determining the TTI within the subframe. For example,the TTI can include a number of symbols which are a subset of aplurality of symbols in the subframe, and the resource grant may begenerated to indicate the TTI duration, the type of communicationtechnology (e.g., ULL), etc., in one example. Moreover, for example, theTTI can be of a symbol duration, multiple symbols duration, slotduration, etc., as described.

At Block 1804, the eNB may transmit the uplink resource grant to the UE.Scheduling component 602 can transmit the uplink resource grant (e.g.,uplink resource grant 1280) to the UE (e.g., UE 1202). As described, forexample, scheduling component 602 can transmit the uplink resource grantto the UE over a downlink control channel in ULL (e.g., using a symbolor other duration of TTI that is less than a subframe). Moreover, theuplink resource grant may indicate one or more aspects regarding uplinkresources, such as an RB group index for an uplink control and/or datachannel, and/or other parameters, which can be used to determine an RBgroup index for transmitting control data, as described above.Transmitting the uplink resource grant, as described, may include theone or more processors 1253 providing data and/or related signalinformation to transceiver 1256 for generating signals to transmit overone or more antennas via an RF front end, etc.

Optionally include, at Block 1806, the eNB may receive control data fromthe UE over resources related to those indicated in the uplink resourcegrant. Scheduling component 602 can receive the control data (e.g., asULL/LTE communication 1282) from the UE (e.g., UE 1202) over theresources related to those indicated in the uplink resource grant. Forexample, scheduling component 602 can receive control data from the UE1202 over resources in a TTI that is an offset number of TTIs from a TTIindicated in the uplink resource grant. Moreover, the eNB reception, atBlock 1806, of the control data may optionally include, at Block 1808,bundled control data for one or more codewords and/or one or morecarriers over the resources. Scheduling component 602 can receive thebundled control data for the one or more codewords and/or one or morecarriers over the resources. As described, this may include receiving asingle ACK/NACK indicator for the codewords and/or carriers (e.g., NACKwhere at least one codeword or carrier indicates NACK, and ACKotherwise). Scheduling component 602 may accordingly retransmit the oneor more codewords over the one or more carriers based on the bundledfeedback.

Optionally include, at Block 1810, the eNB may determine a value for thecontrol data based at least in part on determining a cyclic shift usedto transmit the control data. Scheduling component 602 may determine thevalue for the control data based at least in part on determining thecyclic shift used to transmit the control data. For example, wherescheduling component 602 observes ACK/NACK signaling using a cyclicshift of 0, this may indicate ACK, where a cyclic shift of 6 mayindicate NACK. Similarly, where the control data includes SR andACK/NACK, different cyclic shifting may be used, as described. In anycase, scheduling component 602 may determine control data values basedat least in part on the cyclic shifting.

It is understood that the specific order or hierarchy of steps in theprocesses disclosed is an illustration of exemplary approaches. Basedupon design preferences, it is understood that the specific order orhierarchy of steps in the processes may be rearranged. Further, somesteps may be combined or omitted. The accompanying method claims presentelements of the various steps in a sample order, and are not meant to belimited to the specific order or hierarchy presented.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but is to be accorded the full scope consistentwith the language claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” Unless specifically statedotherwise, the term “some” refers to one or more. All structural andfunctional equivalents to the elements of the various aspects describedherein that are known or later come to be known to those of ordinaryskill in the art are expressly incorporated herein by reference and areintended to be encompassed by the claims. Moreover, nothing disclosedherein is intended to be dedicated to the public regardless of whethersuch disclosure is explicitly recited in the claims. No claim element isto be construed as a means plus function unless the element is expresslyrecited using the phrase “means for.”

What is claimed is:
 1. A method for communicating in a wireless network,comprising: receiving, from a network entity, a resource grantcomprising an indicator of whether to transmit a demodulation referencesignal (RS) for an uplink control channel or an uplink data channel; anddetermining whether to transmit the RS in at least one transmission timeinterval (TTI) based at least in part on the indicator.
 2. The method ofclaim 1, wherein the TTI is a symbol duration in a subframe, and thesubframe comprises a plurality of symbols.
 3. The method of claim 1,wherein the TTI is based on one of an orthogonal frequency divisionmultiplexing (OFDM) symbol or a single-carrierfrequency-division-multiplexing (SC-FDM) symbol.
 4. The method of claim1, further comprising transmitting at least one of a control channel ora data channel in a different TTI as the RS based at least in part onthe resource grant.
 5. The method of claim 4, wherein the RS has atleast one of a bandwidth size, a frequency location, or a number ofantenna ports similar to that of the control channel or the datachannel.
 6. The method of claim 1, further comprising transmitting atleast one of a control channel or a data channel in a same TTI as the RSbased at least in part on the resource grant.
 7. The method of claim 1,wherein the indicator triggers transmission of the RS in two or moredifferent TTIs.
 8. The method of claim 1, wherein the RS is associatedwith at least one of a cyclic shift, a bandwidth, a frequency location,a hopping pattern, a number of antenna ports, or a comb level.
 9. Themethod of claim 1, wherein the indicator is part of a periodic RStrigger for the RS from the network entity.
 10. The method of claim 1,wherein the indicator is part of an aperiodic RS trigger for the RS fromthe network entity.
 11. The method of claim 1, further comprisingreceiving a radio resource control (RRC) communication from the networkentity to configure a periodicity of transmitting the RS.
 12. The methodof claim 1, further comprising receiving the resource grant in downlinkcontrol information from the network entity.
 13. The method of claim 1,further comprising prioritizing transmission of the RS over transmissionof communications in resources over the TTI as specified in the resourcegrant.
 14. The method of claim 13, wherein the resource grantcorresponds to one of a physical uplink control channel, a physicaluplink shared channel, or a sounding reference signal in long termevolution.
 15. A user equipment for communicating in a wireless network,comprising: a transceiver; at least one processor communicativelycoupled with the transceiver via a bus for communicating in the wirelessnetwork; and a memory communicatively coupled with the at least oneprocessor and/or the transceiver via the bus; wherein the at least oneprocessor and the memory are operable to: receive, from a networkentity, a resource grant comprising an indicator of whether to transmita demodulation reference signal (RS) for an uplink control channel or anuplink data channel; and determine whether to transmit the RS in atleast one transmission time interval (TTI) based at least in part on theindicator.
 16. The user equipment of claim 15, wherein the TTI is asymbol duration in a subframe, and the subframe comprises a plurality ofsymbols.
 17. The user equipment of claim 15, wherein the TTI is based onone of an orthogonal frequency division multiplexing (OFDM) symbol or asingle-carrier frequency-division-multiplexing (SC-FDM) symbol.
 18. Theuser equipment of claim 15, wherein the at least one processor and thememory are further operable to transmit, via the transceiver, at leastone of a control channel or a data channel in a different TTI as the RSbased at least in part on the resource grant.
 19. The user equipment ofclaim 15, wherein the at least one processor and the memory are furtheroperable to transmit, via the transceiver, at least one of a controlchannel or a data channel in a same TTI as the RS based at least in parton the resource grant.
 20. The user equipment of claim 15, wherein theRS is associated with at least one of a cyclic shift, a bandwidth, afrequency location, a hopping pattern, a number of antenna ports, or acomb level.
 21. The user equipment of claim 15, wherein the indicator ispart of a periodic RS trigger or an aperiodic RS trigger for the RS fromthe network entity.
 22. The user equipment of claim 15, wherein the atleast one processor and the memory are further operable to receive, viathe transceiver, a radio resource control (RRC) communication from thenetwork entity to configure a periodicity of transmitting the RS. 23.The user equipment of claim 15, wherein the at least one processor andthe memory are further operable to receive, via the transceiver, theresource grant in downlink control information from the network entity.24. The user equipment of claim 15, wherein the at least one processorand the memory are further operable to prioritize transmission of the RSover transmission of communications in resources over the TTI asspecified in the resource grant.
 25. A user equipment for communicatingin a wireless network, comprising: means for receiving, from a networkentity, a resource grant comprising an indicator of whether to transmita demodulation reference signal (RS) for an uplink control channel or anuplink data channel; and means for determining whether to transmit theRS in at least one transmission time interval (TTI) based at least inpart on the indicator.
 26. The user equipment of claim 25, wherein theTTI is a symbol duration in a subframe, and the subframe comprises aplurality of symbols.
 27. The user equipment of claim 25, wherein theTTI is based on one of an orthogonal frequency division multiplexing(OFDM) symbol or a single-carrier frequency-division-multiplexing(SC-FDM) symbol.
 28. A computer-readable storage medium comprisingcomputer-executable code for communicating in a wireless network, thecode comprising: code for receiving, from a network entity, a resourcegrant comprising an indicator of whether to transmit a demodulationreference signal (RS) for an uplink control channel or an uplink datachannel; and code for determining whether to transmit the RS in at leastone transmission time interval (TTI) based at least in part on theindicator.
 29. The computer-readable storage medium of claim 28, whereinthe TTI is a symbol duration in a subframe, and the subframe comprises aplurality of symbols.
 30. The computer-readable storage medium of claim28, wherein the TTI is based on one of an orthogonal frequency divisionmultiplexing (OFDM) symbol or a single-carrierfrequency-division-multiplexing (SC-FDM) symbol.